What is a stem changing word

From Wikipedia, the free encyclopedia

In linguistics, a word stem is a part of a word responsible for its lexical meaning. The term is used with slightly different meanings depending on the morphology of the language in question. In Athabaskan linguistics, for example, a verb stem is a root that cannot appear on its own and that carries the tone of the word.

In most cases, a word stem is not modified during its declension, while in some languages it can be modified (apophony) according to certain morphological rules or peculiarities, such as sandhi. For example in Polish: miast-o («city»), but w mieść-e («in the city»). In English: «sing», «sang», «sung».

Uncovering and analyzing cognation between word stems and roots within and across languages has allowed comparative philology and comparative linguistics to determine the history of languages and language families.[1]

Usage[edit]

In one usage, a word stem is a form to which affixes can be attached.[2] Thus, in this usage, the English word friendships contains the word stem friend, to which the derivational suffix -ship is attached to form a new stem friendship, to which the inflectional suffix -s is attached. In a variant of this usage, the root of the word (in the example, friend) is not counted as a stem (in the example, the variant contains the stem friendship, where -s is attached).

In a slightly different usage, which is adopted in the remainder of this article, a word has a single stem, namely the part of the word that is common to all its inflected variants.[3] Thus, in this usage, all derivational affixes are part of the stem. For example, the stem of friendships is friendship, to which the inflectional suffix -s is attached.

Word stems may be a root, e.g. run, or they may be morphologically complex, as in compound words (e.g. the compound nouns meatball or bottleneck) or words with derivational morphemes (e.g. the derived verbs black-en or standard-ize). Hence, the stem of the complex English noun photographer is photo·graph·er, but not photo. For another example, the root of the English verb form destabilized is stabil-, a form of stable that does not occur alone; the stem is de·stabil·ize, which includes the derivational affixes de- and -ize, but not the inflectional past tense suffix -(e)d. That is, a stem is that part of a word that inflectional affixes attach to.

For example, the stem of the verb wait is wait: it is the part that is common to all its inflected variants.

  1. wait (infinitive)
  2. wait (imperative)
  3. waits (present, 3rd people, singular)
  4. wait (present, other persons and/or plural)
  5. waited (simple past)
  6. waited (past participle)
  7. waiting (progressive)

Citation forms and bound morphemes[edit]

In languages with very little inflection, such as English and Chinese, the stem is usually not distinct from the «normal» form of the word (the lemma, citation or dictionary form). However, in other languages, word stems may rarely or never occur on their own. For example, the English verb stem run is indistinguishable from its present tense form (except in the third person singular). However, the equivalent Spanish verb stem corr- never appears as such because it is cited with the infinitive inflection (correr) and always appears in actual speech as a non-finite (infinitive or participle) or conjugated form. Such morphemes that cannot occur on their own in this way are usually referred to as bound morphemes.

In computational linguistics, the term «stem» is used for the part of the word that never changes, even morphologically, when inflected, and a lemma is the base form of the word.[citation needed] For example, given the word «produced», its lemma (linguistics) is «produce», but the stem is «produc» because of the inflected form «producing».

Paradigms and suppletion[edit]

A list of all the inflected forms of a word stem is called its inflectional paradigm. The paradigm of the adjective tall is given below, and the stem of this adjective is tall.

  • tall (positive); taller (comparative); tallest (superlative)

Some paradigms do not make use of the same stem throughout; this phenomenon is called suppletion. An example of a suppletive paradigm is the paradigm for the adjective good: its stem changes from good to the bound morpheme bet-.

  • good (positive); better (comparative); best (superlative)

Oblique stem [edit]

Both in Latin and in Greek, the declension (inflection) of some nouns uses a different stem in the oblique cases than in the nominative and vocative singular cases. Such words belong to, respectively, the so-called third declension of the Latin grammar and the so-called third declension of the Ancient Greek grammar. For example, the genitive singular is formed by adding -is (Latin) or -ος (Greek) to the oblique stem, and the genitive singular is conventionally listed in Greek and Latin dictionaries to illustrate the oblique.

Examples[edit]

Latin word meaning oblique stem
adeps fat adip-
altitudo height altitudin-
index pointer indic-
rex king, ruler reg-
supellex equipment, furniture supellectil-
Greek word meaning oblique stem
ἄναξ (ánax) lord ἄνακτ- (ánakt-)
ἀνήρ (anḗr) man ἀνδρ- (andr-)
κάλπις (kálpis) jug κάλπιδ- (kálpid-)
μάθημα (máthēma) learning μαθήματ- (mathḗmat-)

English words derived from Latin or Greek often involve the oblique stem: adipose, altitudinal, android, mathematics.

Historically, the difference in stems arose due to sound change in the nominative. In the Latin third declension, for example, the nominative singular suffix -s combined with a stem-final consonant. If that consonant was c, the result was x (a mere orthographic change), while if it was g, the -s caused it to devoice, again resulting in x. If the stem-final consonant was another alveolar consonant (t, d, r), it elided before the -s. In a later era, n before the nominative ending was also lost, producing pairs like atlas, atlant- (for English Atlas, Atlantic).

See also[edit]

  • Lemma (morphology)
  • Lexeme
  • Morphological typology
  • Morphology (linguistics)
  • Principal parts
  • Root (linguistics)
  • Stemming algorithms (computer science)
  • Thematic vowel

References[edit]

  1. ^ Houghton Mifflin Harcourt, The American Heritage Dictionary of the English Language: Indo-European Roots Appendix, Houghton Mifflin Harcourt.
  2. ^ Geoffrey Sampson; Paul Martin Postal (2005). The ‘language instinct’ debate. Continuum International Publishing Group. p. 124. ISBN 978-0-8264-7385-1. Retrieved 2009-07-21.
  3. ^ Paul Kroeger (2005). Analyzing grammar. Cambridge University Press. p. 248. ISBN 978-0-521-81622-9. Retrieved 2009-07-21.
  • What is a stem? — SIL International, Glossary of Linguistic Terms.
  • Bauer, Laurie (2003) Introducing Linguistic Morphology. Georgetown University Press; 2nd edition.
  • Williams, Edwin and Anna-Maria DiScullio (1987) On the definition of a word. Cambridge MA, MIT Press.

External links[edit]

  • Searchable reference for word stems including affixes (prefixes and suffixes)
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A comprehensive article on Stemming

Introduction:

During natural language processing, every day, we face one challenge which is cleaning a text properly. For cleaning text, we often use two methods to modify the texts, which are stemming and lemmatization. In this post, we will analyze about stemming and lemmatization in details.

What is stemming and lemmatization?

For grammatical reasons, we tend to use words that are the same up to a core portion and then end with different suffixes to create different parts of speech as well as different meanings. For example, cars, car, car’s, cars’; all have car as the main part and the last parts make the difference of meaning. While statistically analyzing the text, we need to consider the core parts of these words, to avoid redundancy of the information and other reasons.

From this context, enters stemming and lemmatization. It is important to note that the reason stemming algorithms have been developed is totally different from natural language processing. The main goal of stemming is to create the root of any morphological variation of a word; to ultimately improve Information retrieval quality; i.e. its a product IR processes.] Both stemming and lemmatization attempt to reduce a word to its most irreducible core part. Now, stemming refers to algorithmically reduce a word to its core part i.e. the stem or the root ( don’t confuse these words with their grammatical meaning), whether that core part is a subword or word, is not important. Lemmatization refers also to algorithmically change a word to its core part, but then it ensures that the core part is a word; often using vocabulary or a word dictionary. Therefore, using stemming, you may end up including subwords in text, while lemmatization always ensures that the changed words are also words. In this post, we will focus on stemming algorithms. In the following post, we will discuss the different varieties of lemmatization.

How does Stemming work?

Stemming is the process of producing morphological variants of a root/base word. There are mainly three problems in stemming, namely (1) under-stemming and (2) over-stemming and (3) misstemming. On a high level, a stemmer is either a set of rules, a dictionary guided lookup algorithm of the sort or a hybrid approach of both of them. A rule-based stemmer matches different types of suffixes within the word and then removes them according to these rules, finally to reach the stem of the word. A dictionary-based stemmer relies on a dictionary to find out the relevant stem from a dictionary of words, using the original word to look up in the dictionary. A hybrid approach uses mostly set of rules for both lookup and easy stemming; while uses a dictionary for disambiguation, minimizing misstemming and ruling out exceptions. On these lines, numerous stemmers for English has been created. Some of these stemmers are:

  1. Lovins Stemmer

    The first stemmer written was Lovins stemmer; written by Julie beth lovins. According to wikipedia

    «This paper was remarkable for its early date and had a great influence on later work in this area. Her paper refers to three earlier major attempts at stemming algorithms, by Professor John W. Tukey of Princeton University, the algorithm developed at Harvard University by Michael Lesk, under the direction of Professor Gerard Salton, and a third algorithm developed by James L. Dolby of R and D Consultants, Los Altos, California.»

    Lovins stemmer is the first one to categorize suffix ending and then organize removal of suffices based on conditions, which is also pretty much the core of all other rule-based stemmers.

    «It [Lovins stemmer] performs a lookup on a table of 294 endings, 29 conditions and 35 transformation rules, which have been arranged on the longest-match principle. The Lovins stemmer removes the longest suffix from a word. Once the ending is removed, the word is recoded using a different table that makes various adjustments to convert these stems into valid words. It always removes a maximum of one suffix from a word, due to its nature as a single-pass algorithm. The advantage of this algorithm is it is very fast and can handle the removal of double letters in words like ‘getting’ being transformed to ‘get’ and also handles many irregular plurals like – mouse and mice, index and indices, etc. Drawbacks of the Lovins approach are that it is time and data consuming. Furthermore, many suffixes are not available in the table of endings. It is sometimes highly unreliable and frequently fails to form words from the stems or to match the stems of like-meaning words. The reason being the technical vocabulary being used by the author.» — a description of Lovins stemmer from comparative study of stemming algorithms by Anjali G.jivani.

  2. Dawson Stemmer

    Dawson, J.L., invented the Dawson stemmer in 1974; shortly after the Lovin’s stemmer. This stemmer extends the same approach as the Lovins stemmer with a list of more than a thousand suffixes in the English language. Here is the generic algorithm for the Dawson stemmer:

    1. Get the input word
    2. Get the matching suffix
    3. The suffix pool is reverse indexed by length and the last character
    4. Remove the longest suffix from the word with exact match
    5. Recode the word using a mapping table
    6. Convert stem into a valid word

    The advantages of the Dawson stemmer is that it is a single-pass stemmer. But the main problem with this stemmer is that again, it relies on a mapping table and a reverse indexed storage of suffices. Although that does not make it as slow as a dictionary-based stemmer; still it makes it slower than traditional rule-based ones like porter’s algorithm.

  3. Porter’s Stemmer algorithm

    Porter’s stemmer algorithm was first published in 1980 by M.F.porter and then it has been deeply rediscovered, written in dozens of different languages from that time. Porter stemmer is a 5 step process, which iteratively removes suffixes based on number of conditions specified at each step. Due to this step by step process, it can remove combined suffixes as well as reduces the over stemming part using the conditions. The conditions are mainly based on how many syllables are in a word before the ending and what type of suffix is there at the ending of the word. Each set of rules also obeys the removal of maximum length suffix possible according to the conditions, which is a similarity to its priors like Lovins and dawson.Now, as the algorithm is quite detailed, I will provide proper links to read the details of the stemming process:

    1. Porter stemming process
    2. Porter stemming original paper
    3. research on advances of porter stemming
  4. Snowball stemming language

    Snowball is the standard language developed by M.F.porter for rigorous and unambiguous implementation of stemming algorithms. Snowball can create direct stemming programs in ANSI C or java if the algorithm is properly defined in snowball. It is the current language used by all academics as well as industrial people to write new and standard stemmers.

    Using snowball, porter revised and published an enhanced and improved version of his stemmer, called porter2. This stemmer is sometimes known as snowball stemmer too. NLTK also refers porter2 as Snowball stemmer.

    For porter’s stemmer and snowball stemmer, there exist NLTK modules that implement these processes. The link for how to use them is the following: Nltk resources for porter stemmer

  5. Krovetz Stemmer

    Krovetz Stemmer was proposed in 1993 by Robert Krovetz. While we have been discussing mainly algorithm based stemmers up to this point, Krovetz stemmer is the first hybrid approach with a dictionary and a set of rules. This stemmer, given a word, first look up the dictionary to see if it is a proper word without suffices. If it is, then there is no reason to stem it. While if it is not in the dictionary, we stem it using a set of rules just like other stemmers and then again look up in the dictionary. In this way, Krovetz stemmer ensures that we reach a word, and not a non-word, individually non-sensical subword as a stem.

    While, Krovetz stemmer always reach a word after stemming and also tend to have very less misstemming; the problem with Krovetz is the dictionary. The dictionary, as we know, needs yearly maintenance and updates and generally occupies quite a memory space. Also, the lookup process ends up being a computationally heavy process and therefore, Krovetz stemmer becomes quite slow and sort of inapplicable for large text repositories; where traditional slightly more inaccurate rule-based stemmers are much faster and easily applicable.

  6. Xerox Stemmer

    Computational linguists have developed a stemmer based on a lexicon database with a mapping between surface forms and base forms with proper infrastructure for fast use of the database to transform surface-level words, i.e. words with suffixes and prefixes into search terms for the database. The stemmer works like below on a generic level:

    1. It changes the original words using an inflection database to turn nouns into singular from plural, verbs into infinitive form, pronouns into nominative and adjective into positive form.
    2. These changed words are used to find out the related stems from a derivational database, based on both form and semantics. The use of semantics here reduces the misstemming errors which are often prevalent in porter and snowball stemmer. This derivational database, not only removes suffix but also removes prefix, unlike most of the other stemmers, which focuses solely on removing suffices.
    3. There are also inclusion of special tables for handling irregular forms and exceptions, which goes without saying.

    While being technologically stronger, using prefix removal process, derivational and inflectional database, Xerox stemmer is quite good, it is also limited by the curse of using a dictionary-like database which is supposed to update once a few years and needs maintenance and space to work with. Also, it is not susceptible to work with suffixes or prefixes it does not contain in the database and therefore vulnerable to constant changes in the language.

  7. Statistical stemmers:

    While we have discussed rule-based and dictionary or database dependent stemmers up to this point in this article, there are statistical method based stemmers as well in stemming literature. The main stemmers in this genre are:

    1. N-gram stemmer
    2. Hidden Markov model-based stemmer
    3. YSS based stemmer

    These stemmers require some or the other a bit of different contextual knowledge from machine learning and statistics. Although with this site it is not unfamiliar, considering the scope of this post, I am not going into the details of these stemmers for omitting mention of complicated methods involved with these stemmers. Just to give a high-level idea, these stemmers try to use the contextual reference to stem as well as a hidden language model often to find out the original stem from the raw word. You can read further about it from this paper on comparative study of stemming algorithms.

Stemming on other languages and Conclusion:

We have discussed only the English stemming algorithms in this article. It is important to note that, stemming is not applicable to every language, but mostly to Indo-European languages. One famous language which we can not apply stemming from is Chinese. But in fact, similar algorithms are being developed by computer scientists and linguists from other languages and significant works followed last few years. Being a Bengali myself, I conclude this post with a few references to advances in Bengali stemmer and their implementations.

  1. paper on rule-based Bangla stemmer
  2. Implementation of Bangla stemmer

The paper on the rule-based Bangla stemmer includes a good collection of history for the other different types of stemmers as well. Other than Aryan root languages, works like Tamil stemmer and others also focus on Indian Dravid-rooted languages also. So, if someone is willing to research on stemming Indo-Aryan languages, these references can be a good starting point. I hope you liked the article. Please share with your colleagues and friends for sharing the work as well as a comment if any unwilling mistake is included.

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There are many common, everyday verbs that fall into the category of stem-changing verbs in Spanish. That’s why it’s important to understand what they are and how they work.

We’ve talked a lot about the different irregular verb conjugations in Spanish on this blog, as well as the regular verb conjugations. But there is a certain type of verb that we haven’t really addressed, and it’s somewhere between regular and irregular verbs. Stem-changing verbs in Spanish are conjugated differently from regular verbs, but unlike irregular verbs, they all follow the same pattern.

Please note: if you do not know the conjugations for regular verbs, this post will be confusing for you. First check out our guide to conjugations in Spanish, and then come back to continue.

So, what is a stem and how exactly do these verbs change?

A stem is the part of the verb that comes before the ending (which, in infinitive verbs, is always either ar, er, or ir). In regular conjugations, the stem doesn’t change, where in irregular conjugations, it can be completely different. In stem-changing verbs, the change is in the last vowel of the stem.

Stem-changing verbs in Spanish can also be thought of as 1, 2, 3, 6 verbs. This is because in the traditional conjugation tables, the conjugations that change are the first, second, third and sixth.

Let’s see that visualized.

Stem-changing verbs in Spanish: affected conjugations

1 yo I
2 tú you
3 usted, él, ella you (formal), he, she
4 nosotros we
5 vosotros plural you (informal)
6 ustedes, ellos, ellas plural you (formal), they

In other words, the affected conjugations are in singular, the first person (yo), the second person (tú) and second person formal (usted), the third person (él, ella), and in plural, the second person formal (ustedes), and the third person (ellos, ellas).

It might be easier to think of it as the ones that are not affected as there are fewer: just nosotros and vosotros. In case you were wondering about vos, it is also unaffected. These are conjugated just as they are when it’s a regular verb.

There are a few different ways that stem-changing verbs in Spanish can change. The key is in the vowels in the verb. Let’s see the different possibilities:

  • e -> ie (e.g: pensar)
  • e -> i (eg: conseguir)
  • o -> ue (eg: encontrar)
  • others (i -> ie, u -> ue)

Stem-changing verbs where the e in the stem changes to ie

In the Spanish stem-changing verbs where e conjugates into ie, the last e of the stem turns into ie in the present tense conjugations 1, 2, 3, and 6.

Examples:

1. Pensar | to think

Breakdown:

Pens – ar

Stem: pens

Stem change: e -> ie – pens -> piens

Pensar conjugation

1 yo pienso
2 tú piensas
3 usted, él, ella piensa
4 nosotros pensamos
5 vosotros pensáis
6 ustedes, ellos, ellas piensan

2. Preferir | to prefer

Stem change: prefer -> prefier

Note that the stem changes in the same way no matter whether the verb ends in ar, er, or ir.

Preferir conjugation

1 yo prefiero
2 tú prefieres
3 usted, él, ella prefiere
4 nosotros preferimos
5 vosotros preferís
6 ustedes, ellos, ellas prefieren

3. Entender | to understand

Stem change: entend -> entiend

Entender conjugation

1 yo entiendo
2 tú entiendes
3 usted, él, ella entiende
4 nosotros entendemos
5 vosotros entendéis
6 ustedes, ellos, ellas entienden

4. Empezar | to start

Stem change: empez -> empiez

Note that the change is always on the last syllable of the stem, no matter how many other vowels there are in the verb.

Empezar conjugation

1 yo empiezo
2 tú empiezas
3 usted, él, ella empieza
4 nosotros empezamos
5 vosotros empezáis
6 ustedes, ellos, ellas empiezan

Stem-changing verbs where the e in the stem changes to i

These are similar to the verbs above, except instead of ie, the vowel in the last syllable of the stem just changes to i in the first, second, third and sixth. This type of stem-changing verb tends to be ir-ending verbs only.

Examples:

1. Conseguir | to obtain

Breakdown:

Conseg – (u)ir

Note: the u before the i is there to show that the g in the word is pronounced as a hard g. So this is not considered part of the stem. Some would say that this makes conseguir irregular in the present first person, but since it is caused by a straightforward spelling rule, I wouldn’t consider it as such.

Stem: conseg

Stem change: e -> i – conseg -> consig

Conseguir conjugation

1 yo consigo
2 tú consigues
3 usted, él, ella consigue
4 nosotros conseguimos
5 vosotros coneguís
6 ustedes, ellos, ellas consiguen

2. Servir | to serve

Stem change: serv -> sirv

Servir conjugation

1 yo sirvo
2 tú sirves
3 usted, él, ella sirve
4 nosotros servimos
5 vosotros servís
6 ustedes, ellos, ellas sirven

Stem-changing verbs where the o in the stem changes to ue

Again, once you understand the rules, this is a pretty straightforward vowel change.

Examples:

1. Almorzar | to have lunch

Breakdown:

Almorz – ar

Stem: almorz

Stem change: o -> ue – almorz -> almuerz

Almorzar conjugation

1 yo almuerzo
2 tú almuerzas
3 usted, él, ella almuerza
4 nosotros almorzamos
5 vosotros almorzáis
6 ustedes, ellos, ellas almuerzan

2. Encontrar | to find

Stem change: econtr -> encuentr

Encontrar conjugation

1 yo encuentro
2 tú encuentras
3 usted, él, ella encuentra
4 nosotros encontramos
5 vosotros encontráis
6 ustedes, ellos, ellas encuentran

3. Mover | to move

Stem change: mov -> muev

Mover conjugation

1 yo muevo
2 tú muevas
3 usted, él, ella mueva
4 nosotros movemos
5 vosotros movéis
6 ustedes, ellos, ellas mueven

4. Dormir | to sleep

Stem change: dorm -> duerm

Dormir conjugation

1 yo duermo
2 tú duermes
3 usted, él, ella duerme
4 nosotros dormimos
5 vosotros dormís
6 ustedes, ellos, ellas duermen

Other possible stem-changing verbs in Spanish

The above mentioned three types of stem-changing verbs in Spanish are, without a doubt, the main stem-changing verbs. However, there are two other types which we also see, albeit there are much fewer of those. They are so uncommon, in fact, that it is easier to remember the one common verb that follows each conjugation than it is to remember the conjugation itself.

Example 1: jugar | to play (u->ue)

Breakdown:

Jug – ar

Stem: jug

Stem change: u -> ue – jug -> jueg

Jugar conjugation

1 yo juego
2 tú juegas
3 usted, él, ella juega
4 nosotros jugamos
5 vosotros jugáis
6 ustedes, ellos, ellas juegan

Example 2: adquirir | to acquire (i->ie)

Breakdown:

Adquir – ir

Stem: adquir

Stem change: i -> ie – adquir -> adquier

Adquirir conjugation

1 yo adquiero
2 tú adquieres
3 usted, él, ella adquiere
4 nosotros adquirimos
5 vosotros adquirís
6 ustedes, ellos, ellas adquieren

How can you tell if a Spanish verb is a stem-changing verb?

Unfortunately, there is no real way to know just by looking at a verb whether it is regular, stem-changing, or even irregular. This is one of those things that you just have to memorize. It might sound bad, but really this is something you will often just pick up in normal speech. For example, if you have heard of the verb pedir and you hear people saying pido and pides etc. all the time, you can confidently assume that pedir is an e->i stem-changing verb. As a Spanish learner, I can’t tell you the last time I had to think about whether a verb was stem-changing or irregular as all the differences have been acquired into my speech for a long time. So don’t think it’s not possible!

If, however, you want to find all the stem-changing verbs there are and attempt to memorize them, there is nothing wrong with that. However, there really are many stem-changing verbs in Spanish, so a complete list is hard to come by. The best I have found is here (you have to click into each category of cambio de raíz).

If you are learning by doing a course or using a textbook, whenever a new word is introduced, you should be told if it is stem-changing. The way this is communicated will vary from textbook to textbook, but in my text books they would just write the stem change next to the new infinitive verb. For example:

  • Arrepentirse (ie)
  • Recordar (ue)
  • Elegir (i)

Another way you can get to know the stem-changing verbs in Spanish faster is by looking at the root verb. Many Spanish verbs are prefixed forms of simpler verbs. For example, we’ve talked about pedir and now know it as a stem-changing verb. So seeing despedir, we can safely assume it is also a stem-changing verb of the same category. In this case, the two verbs have unrelated meanings, but that doesn’t matter.

Do Spanish stem-changing verbs change in other tenses and conjugations?

In this post, we have talked about how the stem-changing verbs in Spanish change in the present tense. Stem-changing verbs generally only change their stems in the present tense (including present indicative, present subjunctive, and present imperative, i.e. commands). However, that doesn’t make the other conjugations necessarily regular. Some good examples of verbs that are stem-changing in the present tense, while irregular in other tenses, are querer (ie), poder (ue), and tener (ie).

The only exception to the rule that stem-changing verbs change only in the present tense are the e -> i category of stem-changing verbs. In this case, the stem also changes:

  • in the gerund (e.g sirviendo)
  • in the past preterite third person – only singular and plural (e.g sirvió, sirvieron)
  • in the imperfect preterite – all 6 conjugations (e.g: sirviera, sirvieses). This conjugation and how it’s formed is explained in our post about all the Spanish tenses

So, you should now understand what stem-changing verbs in Spanish are. Practice using them in context with Clozemaster!

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Examples
The stem of the verb wait is wait: it is the part that is common to all its inflected variants.

  1. wait (infinitive)
  2. wait (imperative)
  3. waits (present, 3rd person, singluar)
  4. wait (present, other persons and/or plural)
  5. waited (simple past)
  6. waited (past participle)
  7. waiting (progressive)

In linguistics, a stem is a part of a word. The term is used with slightly different meanings.

In one usage, a stem is a form to which affixes can be attached.[1] Thus, in this usage, the English word friendships contains the stem friend, to which the derivational suffix -ship is attached to form a new stem friendship, to which the inflectional suffix -s is attached. In a variant of this usage, the root of the word (in the example, friend) is not counted as a stem.

In a slightly different usage, which is adopted in the remainder of this article, a word has a single stem, namely the part of the word that is common to all its inflected variants.[2] Thus, in this usage, all derivational affixes are part of the stem. For example, the stem of friendships is friendship, to which the inflectional suffix -s is attached.

Stems may be roots, e.g. run, or they may be morphologically complex, as in compound words (cf. the compound nouns meat ball or bottle opener) or words with derivational morphemes (cf. the derived verbs black-en or standard-ize). Thus, the stem of the complex English noun photographer is photo·graph·er, but not photo. For another example, the root of the English verb form destabilized is stabil-, a form of stable that does not occur alone; the stem is de·stabil·ize, which includes the derivational affixes de- and -ize, but not the inflectional past tense suffix -(e)d. That is, a stem is that part of a word that inflectional affixes attach to.

The exact use of the word ‘stem’ depends on the morphology of the language in question. In Athabaskan linguistics, for example, a verb stem is a root that cannot appear on its own, and that carries the tone of the word. Athabaskan verbs typically have two stems in this analysis, each preceded by prefixes.

Contents

  • 1 Citation forms and bound morphemes
  • 2 Paradigms and suppletion
  • 3 See also
  • 4 References
  • 5 External links

Citation forms and bound morphemes

In languages with very little inflection, such as English and Chinese, the stem is usually not distinct from the «normal» form of the word (the lemma, citation or dictionary form). However, in other languages, stems may rarely or never occur on their own. For example, the English verb stem run is indistinguishable from its present tense form (except in the third person singular); but the equivalent Spanish verb stem corr- never appears as such, since it is cited with the infinitive inflection (correr) and always appears in actual speech as a non-finite (infinitive or participle) or conjugated form. Morphemes like Spanish corr- which can’t occur on their own in this way, are usually referred to as bound morphemes.

In computational linguistics, a stem is the part of the word that never changes even when morphologically inflected, whilst a lemma is the base form of the verb. For example, given the word «produced», its lemma (linguistics) is «produce», however the stem is «produc»: this is because there are words such as production. [3]

Paradigms and suppletion

A list of all the inflected forms of a stem is called its inflectional paradigm. The paradigm of the adjective tall is given below, and the stem of this adjective is tall.

  • tall (positive); taller (comparative); tallest (superlative)

Some paradigms do not make use of the same stem throughout; this phenomenon is called suppletion. An example of a suppletive paradigm is the paradigm for the adjective good: its stem changes from good to the bound morpheme bet-.

  • good (positive); better (comparative); best (superlative)

See also

  • Lemma (morphology)
  • Lexeme
  • Morphological typology
  • Morphology (linguistics)
  • Principal parts
  • Root (linguistics)
  • Stemming algorithms (Computer science)
  • Vowel stems

References

  1. ^ Geoffrey Sampson; Paul Martin Postal (2005). The ‘language instinct’ debate. Continuum International Publishing Group. p. 124. ISBN 9780826473851. http://books.google.de/books?id=N0zJNPuXTZMC&pg=PA124&lpg=PA124&dq=%22a+root+is%22+%22a+stem+is%22&source=bl&ots=Amv01e0fmE&sig=p1LNjJBk5iHCDqpf7IDzRKGG3sY&hl=en&ei=bSZmSqCwAYegngOXlJH4Dw&sa=X&oi=book_result&ct=result&resnum=1. Retrieved 2009-07-21.
  2. ^ Paul Kroeger (2005). Analyzing grammar. Cambridge University Press. p. 248. ISBN 9780521816229. http://books.google.com/books?id=rSglHbBaNyAC&pg=PA248&dq=%22a+stem+is%22+%22a+root+is%22&ei=4CxmSvaCHIqyzQSOg6XpAw&hl=de. Retrieved 2009-07-21.
  3. ^ http://nltk.sourceforge.net/index.php/Book
  • What is a stem? — SIL International, Glossary of Linguistics Terms.
  • Bauer, Laurie (2003) Introducing Linguistic Morphology. Georgetown University Press; 2nd edition.
  • Williams, Edwin and Anna-Maria DiScullio (1987) On the definition of a word. Cambridge MA, MIT Press.

External links

  • Searchable reference for word stems including affixes (prefixes and suffixes)
Источник
Examples
The stem of the verb wait is wait: it is the part that is common to all its inflected variants.

  1. wait (infinitive)
  2. wait (imperative)
  3. waits (present, 3rd person, singular)
  4. wait (present, other persons and/or plural)
  5. waited (simple past)
  6. waited (past participle)
  7. waiting (progressive)

In linguistics, a stem is a part of a word. The term is used with slightly different meanings.

In one usage, a stem is a form to which affixes can be attached.[1] Thus, in this usage, the English word friendships contains the stem friend, to which the derivational suffix -ship is attached to form a new stem friendship, to which the inflectional suffix -s is attached. In a variant of this usage, the root of the word (in the example, friend) is not counted as a stem.

In a slightly different usage, which is adopted in the remainder of this article, a word has a single stem, namely the part of the word that is common to all its inflected variants.[2] Thus, in this usage, all derivational affixes are part of the stem. For example, the stem of friendships is friendship, to which the inflectional suffix -s is attached.

Stems may be a root, e.g. run, or they may be morphologically complex, as in compound words (e.g. the compound nouns meat ball or bottle opener) or words with derivational morphemes (e.g. the derived verbs black-en or standard-ize). Hence, the stem of the complex English noun photographer is photo·graph·er, but not photo. For another example, the root of the English verb form destabilized is stabil-, a form of stable that does not occur alone; the stem is de·stabil·ize, which includes the derivational affixes de- and -ize, but not the inflectional past tense suffix -(e)d. That is, a stem is that part of a word that inflectional affixes attach to.

The exact use of the word ‘stem’ depends on the morphology of the language in question. In Athabaskan linguistics, for example, a verb stem is a root that cannot appear on its own, and that carries the tone of the word. Athabaskan verbs typically have two stems in this analysis, each preceded by prefixes.

Uncovering and analyzing cognation between stems and roots within and across languages has allowed comparative philology and comparative linguistics to determine the history of languages and language families.[3]

Contents

  • 1 Citation forms and bound morphemes
  • 2 Paradigms and suppletion
  • 3 See also
  • 4 References
  • 5 External links

Citation forms and bound morphemes

In languages with very little inflection, such as English and Chinese, the stem is usually not distinct from the «normal» form of the word (the lemma, citation or dictionary form). However, in other languages, stems may rarely or never occur on their own. For example, the English verb stem run is indistinguishable from its present tense form (except in the third person singular). However, the equivalent Spanish verb stem corr- never appears as such, because it is cited with the infinitive inflection (correr) and always appears in actual speech as a non-finite (infinitive or participle) or conjugated form. Such morphemes that cannot occur on their own in this way, are usually referred to as bound morphemes.

In computational linguistics, a stem is the part of the word that never changes even when morphologically inflected, whereas a lemma is the base form of the word. For example, given the word «produced», its lemma (linguistics) is «produce», however the stem is «produc», because there are words such as production.[4]

Paradigms and suppletion

A list of all the inflected forms of a stem is called its inflectional paradigm. The paradigm of the adjective tall is given below, and the stem of this adjective is tall.

  • tall (positive); taller (comparative); tallest (superlative)

Some paradigms do not make use of the same stem throughout; this phenomenon is called suppletion. An example of a suppletive paradigm is the paradigm for the adjective good: its stem changes from good to the bound morpheme bet-.

  • good (positive); better (comparative); best (superlative)

See also

  • Lemma (morphology)
  • Lexeme
  • Morphological typology
  • Morphology (linguistics)
  • Principal parts
  • Root (linguistics)
  • Stemming algorithms (computer science)
  • Thematic vowel

References

  1. ↑ Geoffrey Sampson; Paul Martin Postal (2005). The ‘language instinct’ debate. Continuum International Publishing Group. p. 124. ISBN 978-0-8264-7385-1. Retrieved 2009-07-21.<templatestyles src=»Module:Citation/CS1/styles.css»></templatestyles>
  2. ↑ Paul Kroeger (2005). Analyzing grammar. Cambridge University Press. p. 248. ISBN 978-0-521-81622-9. Retrieved 2009-07-21.<templatestyles src=»Module:Citation/CS1/styles.css»></templatestyles>
  3. ↑ Houghton Mifflin Harcourt, The American Heritage Dictionary of the English Language: Indo-European Roots Appendix, Houghton Mifflin Harcourt.<templatestyles src=»Module:Citation/CS1/styles.css»></templatestyles>
  4. ↑ http://nltk.sourceforge.net/index.php/Book
  • What is a stem? — SIL International, Glossary of Linguistics Terms.
  • Bauer, Laurie (2003) Introducing Linguistic Morphology. Georgetown University Press; 2nd edition.
  • Williams, Edwin and Anna-Maria DiScullio (1987) On the definition of a word. Cambridge MA, MIT Press.

External links

  • Searchable reference for word stems including affixes (prefixes and suffixes)eo:Radiko#Lingvo
Источник

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