There are no specific rules in English that prohibit us from starting sentences with certain words. Take starting a sentence with so, for example. Some people believe it shouldn’t happen, but they buy into a myth. This article will explore how to start a sentence with “so.”
You can start a sentence with “so” as a discourse marker or a filler word. We do this when trying to think of something to say before we say it. We can also use “so” to start a new clause related to the previous one, like how “therefore” works.
There are no rules that tell us that we can or cannot start a sentence with a specific word. It’s a common myth that’s passed around that words like “and,” “so,” and “but” cannot begin sentences, but we have proven before how wrong this tale is.
What Does “So” Mean At The Beginning Of A Sentence?
“So” is synonymous with the conjunctive “therefore.” We need a clause or sentence to come before it so that it makes sense. Depending on the content of your writing, you might find that a period is sometimes more suitable than a comma or semi-colon.
For example:
- I didn’t want to do that, and I wasn’t going to be happy about it, so I made sure to stay away from them.
- I didn’t want to do that, and I wasn’t going to be happy about it. So I made sure to stay away from them.
As you can see, the first example is grammatically correct, but it’s too long and wordy. Many people will shy away from wanting to read it, and they’ll be put off by the number of commas and the seemingly endless breath they need to take.
The second example removes the third comma before “so” and replaces it with a period. Here, we start a new sentence with “so.” It still relates to the previous sentence, but we’re doing it in a way that makes it more readable and much less wordy.
Examples Of How To Use “So” At The Beginning Of A Sentence
As we’ve mentioned before, it’s most likely that you’ll use “so” as a filler word or as a way to link back to a previous sentence. We’ll include both cases in this section to understand what we mean.
Filler Word
- So, would you like to do anything with me tonight?
- So, I’ve got this great story to tell you about what happened!
- So, is there anything else you’d like to tell me?
- So, do you know how long it will be until they get here?
- So, I found the funniest little piece of information at the workshop today!
As a filler word, “so” is just a way for people to stall for time or to set up a conversation. We can use it before a statement or a question to try and get someone’s attention or to give us time to think about what to say next.
Linking To The Previous Sentence.
- I wasn’t going to have it, and I wanted them to know that. So I wrote them a strongly worded email.
- He didn’t need to be here, and I wish you didn’t invite him. So next time, make sure you don’t make the same mistake.
- You shouldn’t have done that because everyone’s mad at you. So you’ll need to apologize when you see everyone again.
- We did everything that our parents asked of us, and they still expect more. So we decided that we’d rather come to school earlier!
- They thought they got away with it, and they made jokes about it. So I thought I’d remind them about what they did!
“So” can start a sentence as long as it relates to the previous sentence. We use it as a connective word, which can have a comma before it, but we often replace the comma with a period when the previous sentence would be too wordy with “so” a part of it.
Can You Start A Sentence With “So Much So”?
There are a few other “so” constructs that you might come across. It would help to understand how they work to learn whether “so” can still start a sentence in these forms.
You can start a sentence with “so much so” when we want to talk about the extent to which someone is willing to do something. It has to relate back to the previous sentence when written in this way.
- He was in love with me. So much so that he sent me flowers every single day that he was in my city.
- She didn’t want to be here. So much so that she threw a tantrum so that she could be escorted out.
We do not need any punctuation after “so much so.” It works in a similar way to “so” on its own, where no commas are needed to break it up directly after.
Can You Start A Sentence With “So Far”?
You can start a sentence with “so far” when you want to talk about something that’s happened as expected up until the current time. It doesn’t need to link to any previous sentences, making it a useful way to start a sentence with “so.”
- So far, nobody has given me any bright ideas to play around with.
- So far, you’ve all failed to impress me!
- So far, I’m not looking forward to going to college in the new year.
When using “so far,” we must place a comma after “far.” It requires the comma because it becomes its own clause that adds extra information to the sentence but can also be removed.
Can You Start A Sentence With “So That”?
You can start a sentence with “so that” when you want to talk about what will happen due to an event or what has happened related to a previous sentence. You don’t always need a sentence prior to “so that” for it to work.
- So that nobody gets any bright ideas, I’m going to take away this television set!
- So that people can see I mean business, I’m going to make sure you all know what I’m capable of.
“So that” requires no extra punctuation and can come at the start of a sentence to demonstrate the expected effect of something.
Where Should I Place The Comma When Using “So” At The Beginning Of A Sentence?
Let’s go back to using “so” on its own at the start of a sentence. We need to know about certain grammatical rules related to commas when using it.
You should place a comma after “so” when it’s used as a filler word. It adds nothing to the sentence and is its own clause, allowing us to remove it and keep the original meaning. However, no commas are required when “so” relates to the previous sentence.
- So, do you think you can dance?
As a filler word, the comma must come directly after “so.” This shows that we can remove the filler word if need be, and it added nothing extra to the conversation or question.
- He wasn’t there. So I made his bed for him.
When linked to the previous sentence, we instead need no commas. “So” continues on the next clause and is a part of it, meaning that we can’t include a comma, and it can’t be removed as the sentence won’t make sense.
Can You Use “So” At The Beginning Of A Sentence In Formal Writing?
Since no grammatical rules tell us what words we can and can’t use, there is nothing wrong with using “so” at the beginning of a sentence in formal writing.
We can use “so” at the beginning of a sentence in most cases. When linking back to a previous sentence, you can use “so” formally at the start to demonstrate this. However, “so” should never be formally used as a filler word.
Filler words don’t exist in formal writing, and they should never be used.
Alternatives To Starting A Sentence With “So”
We’ve briefly mentioned that “so” has the same meaning as “therefore” when we start a sentence with it.
There are also a few other alternatives that work in the same way, and we believe these synonyms will be your best hope of starting a sentence with something other than “so.”
- Therefore
- Hence
- Ergo
- Accordingly
- Thus
- Wherefore
- In consequence
- Due to this
- For this reason
Can You End A Sentence With “So”?
Again, there are no specific rules that tell us we can or cannot put a certain word in certain parts of a sentence. The only thing that dictates whether words can go at the end of a sentence is whether they make any logical sense.
There are no logical or grammatical cases where “so” works at the end of a sentence. In most cases, we will avoid using it. The only acceptable case would be the question “how so?”
- How so?
This is the only case where “so” works at the end of a sentence, and it’s because it’s a short question format that people use to ask for further clarification.
In sentences, “so” never works at the end because it’s a conjunction, which works best at the beginning or in the middle of a sentence.
Martin holds a Master’s degree in Finance and International Business. He has six years of experience in professional communication with clients, executives, and colleagues. Furthermore, he has teaching experience from Aarhus University. Martin has been featured as an expert in communication and teaching on Forbes and Shopify. Read more about Martin here.
Anyone sitting in an English grammar class prior to 2010 probably remembers their teacher getting on a soapbox about beginning a sentence with “so,” “but,” and “because.” Despite this, the stubborn use of “so” to introduce a sentence has only grown in verbal and casual writing.
Yes, you may begin a sentence with “so” correctly. Typically, this is the function of a conjunctive “so,” tying the new sentence to the previous one. An adverbial “so” may occasionally start a sentence meaning “thus” or “as a result.” Further, adverbial phrases like “so far as I know” are also appropriate for starting a sentence.
There is a lot to unpack with “so” because it is amazingly flexible. In fact, there are times when starting a sentence with adverbial or conjunctive “so” is incorrect. So, how do we know?
Is It Grammatically Correct to Start a Sentence With “So”?
It is grammatically correct to start a sentence with “so” in certain situations. “So” may appear at the beginning of a sentence as a conjunction, an adverb, an adverbial phrase, and even an adjective in some cases.
“So” can perform many grammatical functions. Some of these may correctly begin a sentence.
The Conjunction “So”
The most common way of correctly using “so” at the beginning of a sentence is to connect it to whatever we’ve stated or has happened previously.
- So, there he was on the brink of a new discovery when the dog rushed under the table.
Notice that these examples focus on connecting ideas for the flow of conversation, not on connecting independent clauses. Further, putting “so” later in the sentence won’t work, so it isn’t functioning as a subordinating conjunction either.
Another way to use the conjunction “so” at the beginning of a sentence is as a way to check for understanding by repeating a point.
- So we are not going to show up until Friday morning, right?
Placing conjunctive “so” at the beginning of a sentence is also possible when referring to a discovery or an epiphany.
- So that’s how the raccoons keep getting into the house!
You can utilize “so” to emphasize what you are about to say.
- So, we have arrived where our diet began — a donut shop.
When asking a question about current events or points of interest, it is appropriate to use “so” at the beginning.
- So, what kind of music do you like to listen to?
One other use of conjunctive “so” at the beginning of a sentence is in agreement with what someone said, but you do not think it is important (source).
- So he’s not the same guy in the profile picture — he’s still a nice guy.
The Adverb “So”
Adverbial “so” can introduce a new topic, a comment on what someone said, or a question about something someone said.
- So, how did it go?
- So, according to your chore track record, Jack, you won’t get your full allowance.
As a subordinating conjunction at the beginning of an adverbial clause, “so” might be at the beginning of the sentence.
- So the horses wouldn’t get out, Susan closed the gate.
Adverbial “so” can modify another word at the beginning of the sentence.
- So many people showed up to the concert!
We may place some adverbial phrases beginning with “so” at the beginning of a sentence, too.
- So far as I know, fast food kitchens are squeaky clean.
- So much for a quick meal; it’s been 45 minutes since we ordered.
- So as to be professional, Charlie put on his best suit.
- So what?
- So far, so good.
- So long!
The Adjective “So”
Less often, “so” may appear in the adjective form at the beginning of a sentence.
- So be it.
What Does “So” Mean?
Due to a vast array of functions, “so” can mean multiple things. The adverb “so” can mean “in the same way,” “thus,” “then,” “very,” or “indeed.” As a conjunction, “so” means “in order that” or “therefore.” The adjective “so” can communicate “true.”
The Adverb
In its adverb form, “so” has a greater range of meaning. It indicates “in the same way” or “also.” It can also mean “thus” or “subsequently.”
- I told you so.
- Dawn enjoys art and so does he.
- Jake will be there, or so he said.
- And so they went.
In terms of measuring the extent of something, “we can define so” as “very” or “extremely.” In terms of measurement, “so” also means “indeed” or “surely.”
- There are so many people!
- You did so.
- I so disagree with you.
“So” may also mean “therefore” or “consequently.”
- Chase has lied before, so we can’t trust him.
The Conjunction
As a conjunction, “so” means “as a result” or “in order that.”
- Josh spent a lot of time on that paper, so he got an A.
- Be quiet so you don’t wake the baby!
The conjunction “so” can also mean “therefore.”
- She told me to stop, so I did.
“So” can communicate that a point is just not important.
- So what?
- So much for that.
To indicate surprise, someone may use “so.”
- So, it was her!
The Adjective
The meaning of the adjective “so” ranges from “true” to “adherence to the right order.”
- Sherri said it was not so.
- James’s OCD requires that his pencils are situated just so.
The Pronoun
The meaning of “so” in the pronoun function is that of whatever it replaces. It can also mean “the same” (source).
- I haven’t seen him in a week or so.
- If you haven’t filed your taxes yet, do so before the 15th.
How Do You Use “So”?
“So” communicates a range of meanings depending on how you use it. It may function as an adverb, conjunction, or adjective. Where you place it in the sentence often depends upon its role in the sentence and what you want to say.
To determine how to use “so” in the sentence, you must first decide whether you need it to modify a word or stand alone. If you need to modify a word, you should use it adverbially or adjectivally. In contrast, you can use “so” as a conjunction to show a relation.
Modifying Another Word
As an adjective, “so” looks odd. It seems like it stands alone, but a closer look will reveal that it describes something’s conformation or order (source).
- It is not so. (describing “it”)
- She styles her hair just so. (describing “hair”)
You can use “so” in several ways and places as an adverb. Here are some of the most common:
| also | He is tall, and so is she. |
| degree | The fish seemed so happy. |
| very | I love you so much. |
| surely | I so want to hide right now. |
| therefore | The ice cream melted and was so undesirable. |
Conjunction
You can use “so” as a coordinating conjunction to join two equal thoughts or a subordinating conjunction to introduce an adverbial clause.
As a coordinating conjunction, “so” most often joins two related independent clauses within the same sentence.
- I needed some tomatoes, so I went to the store.
Though you could write these two sentences out individually, this is unnecessary since they go together easily and avoid the awkwardness of putting a coordinating conjunction “so” at the beginning of the sentence.
However, when the independent clauses on either side add some dependent clauses, it may be cleaner and less confusing to break the two sentences at “so.”
While preparing to make some spaghetti sauce, I needed some tomatoes. So I went to the store before I finished chopping the vegetables to buy some tomatoes.
As a subordinating conjunction, “so” connects a dependent adverbial clause to the sentence. Adverbial clauses are flexible, so we can place them after the clause they modify or before it.
- I left the house so you would miss me.
- So you would miss me, I left the house.
Notice that we follow a dependent clause headed by subordinating conjunction “so” with a comma when it comes before the independent clause. Also note that it is acceptable grammar to begin a sentence with “so” starting an adverb dependent clause.
When Can You Use “So”?
You can use “so” to indicate how much or to what extent something is: “That sandwich is so good” or “This coffee is so hot.”
You can also use “so” to emphasize what you say or to introduce a new topic or question: “So, we meet again” or “So, what do you think about that yellow?”
Using “so” before you repeat a point to make sure everyone is on the same page is appropriate: “So we are meeting at the theater tonight at 8:00, right?”
Another way you can use “so” is to describe the result of something: “He spit on her hand, so she slapped his face.”
Additionally, you may use “so” to join two related sentences: “I really like dogs, so I adopted a puppy.”
You may even attach a related incomplete thought to a complete thought with “so”: “He shut the door so the puppy wouldn’t run outside.”
In What Context Can You Use “So”?
You can use “so” to emphasize words and phrases adverbially in speech but not in formal writing. Instead, we ought to replace phrases like “so good” with “excellent” in formal writing for conciseness.
In terms of connecting sentences, “so” is appropriate in speech or writing, but stronger, clearer subordinating conjunctions like “therefore” are preferable in formal writing.
Using “So” in a Full Sentence
In a full sentence, “so” can appear in many places depending upon the function. Typically, “so” appears within the sentence to modify a verb, adjective, or another adverb. However, the conjunction “so” can appear at the beginning of the sentence.
The adjective “so” is likely to appear at the end of a sentence or at least sometime after the noun it modifies: “He considers them so.”
Adverbial “so” often modifies other words in the sentence: “The kids are so hungry.”
Coordinating conjunction “so” is usually between two independent clauses: “Harry is a wizard, so he must learn spells.”
Subordinating conjunction “so” joins a dependent clause to an independent clause, but it can do this in two ways:
- Jerry cleaned the kitchen so she would be happy.
- So she would be happy, Jerry cleaned the kitchen.
When Not to Use “So” at the Start of a Sentence
Do not use “so” at the start of a sentence if it is a coordinating conjunction that could easily join the two independent clauses together.
- He insisted that he could do it. So, I let him.
However, we could easily combine these two sentences into one to make “so” a coordinating conjunction that links two independent clauses within one sentence.
- He insisted that he could do it, so I let him.
Do not put a dependent clause beginning with “so” alone because it is not a complete thought. It must have an independent clause to complete it.
- Incorrect: So they could learn Chinese.
- Correct: So they could learn Chinese, Mary hired a Chinese tutor.
What Can You Use Instead of “So”?
What you use to replace “so” at the beginning of a sentence depends entirely on what you are communicating. If you attempt to link a sentence to something you’ve previously said, use a different conjunction. You may often simply drop an adverbial “so.”
Depending on the context, you may opt to use transition words like “therefore,” “thus,” “as a result,” or “consequently” instead of “so.” Because “so” is such a common and flexible word, people often overuse it.
Generally speaking, you ought to swap the conjunction “so” out for stronger subordinating conjunctions and adverbial extent “so” with stronger adjectives (or drop it altogether) whenever you can in writing.
Coordinating Conjunctions
Coordinating conjunctions join two equal words, phrases, or clauses. They are “for,” “and,” “nor,” “but,” “or,” “yet,” and “so” or FANBOYS. Coordinating conjunctions do not typically begin a sentence, but they may if the two equal sentences they link are too long to remain clear when combined.
Coordinating conjunctions do not normally start a sentence because their purpose is to join two equivalent items: “Tom likes fish, so he eats fish often.”
In cases where both sentences are strongly related but complex (already made up of multiple clauses), it may be an improvement to keep the sentences independent and show their relationship by starting the second with a coordinating conjunction.
Jace and Emma are both dedicated athletes because they exercise for five hours a day. Yet, they are never satisfied with their achievements because they set new goals for growth.
This article was written for strategiesforparents.com.
Obviously, this gets into matters of style versus grammar. Technically, joining the two sentences would still be grammatically correct, but you should consider style concerns and the need to give your reader a break.
For more on sentence structure and style, consider reading “Can You End a Sentence With Did?” “Can You End a Sentence with Is?” “Is it Correct to Start a Sentence With And?” and “Do You End a Question With For?”
Final Thoughts
Using “so” at the opening of a sentence can generate lots of anxiety for such a small word. If you stick with either replacing “so” with more varied subordinating conjunctions, you will avoid much of the debate around beginning a sentence with “so.”
However, don’t be afraid to begin a sentence with “so,” as it is generally correct. Whether or not you do so between independent sentences is largely up to personal choice. So, what do you think?
- “So” can function as different parts of speech, most commonly an adverb or coordinating conjunction.
- When speaking, using “so” in casual conversation is generally accepted.
- However, in writing, “so” should not start sentences unless used in dialogue.
Throughout conversation and writing, the word “so” appears regularly. There are plenty of rules for its proper usage, but one of the most disputed topics relates to when the word appears at the beginning of a sentence.
Teens, in particular, are fond of using conjunctions to start sentences, both in dialogue and in their writing. However, the conventions of the spoken word differ from those found in writing because additional measures and inflections are present in speech to help with understanding and context.
Plus, when having a conversation with friends and family, there is a certain level of safety from grammatical criticism that allows a more casual use of English conventions.
The question remains – when is it acceptable to begin a sentence with “so?”
How “So” is Used in a Sentence
“So” can function as various parts of speech but most commonly as a conjunction or adverb, meaning the word will follow the basic rules of that type except in exceptional circumstances.
“So” as an Adverb
An adverb modifies an adjective, verb, or even other adverbs. When functioning in this way, “so” usually adds an element of emphasis.
- Jason is so stupid because he thinks he has a chance with Leanne.
Used in this way, “so” emphasizes the adjective “stupid,” generating a heightened sense of his perceived lack of intelligence in this scenario.
- I am so hungry that I could eat a horse!
In this sentence, “so” adds significance to the adjective hungry, setting up this hyperbolic cliché (overused exaggeration).
- I have so much homework to do.
Here, the adverb also plays an essential role in helping the reader (or listener) understand the amount of homework this student must complete.
“So” as a Coordinating Conjunction
Coordinating conjunctions have one principal purpose: to join two complete sentences. Remember, a complete sentence has both a subject and verb while standing alone as a complete thought.
Here is an example of a complete sentence:
- Jessica ate the mysterious red berries.
Our subject is “Jessica,” as she is the person, place, or thing performing an action or receiving an adjective through a linking verb. In this case, she is doing something – eating.
Because eating is an action, that is our verb for the sentence. A verb is either an action (doing something) or linking (joining the subject to another word that describes or modifies it).
Finally, there is more to the sentence that completes the thought. What did Jessica eat? She ate the mysterious red berries.
Altogether, that sentence is a single complete idea and can stand independently without needing any help.
Let’s look at how “so” can function as a conjunction to join two sentences together. Remember that each conjunction creates a relationship between the two independent sentences – “so” indicates a cause and effect/result relationship.
Sentence 1: Jessica ate the mysterious red berries.
Sentence 2: She became incredibly sick.
Sentence 1 + conjunction + Sentence 2:
- Jessica ate the mysterious red berries, so she became incredibly sick.
Notice the comma before “so,” which is a basic grammar rule. When a coordinating conjunction (also known as the FANBOYS – for, and, nor, but, or, yet, so) joins two sentences, there will be a comma before that conjunction.
Here are a few more sentences using “so” in all its conjunctive glory:
- Rodger whistled at Michaela, so she punched him in the face.
- The dog ran into the street, so the car slammed on its brakes.
Note the cause and effect relationship and how it joins two independent clauses (sentences).
Can You Begin a Sentence with “So”
Well, of course, you can begin a sentence with “so,” and people do so all the time, but . . . should you?
The answer is “maybe.”
If you are talking with your friends or family and have no fear of being judged, go for it. Everyone will understand what you mean, and life will probably go on as usual.
However, if you want to write or speak properly in the English language, beginning a sentence with any conjunction is a huge no-no.
When beginning with “so,” what comes next is going to be an incomplete sentence –
- So much homework!
- So, John was late.
The idea here is not complete. While in dialogue, “so” is often used as an interjection when there is a long pause in conversation or to prompt a response, which is generally accepted. Otherwise, it should be joining one sentence to another.
Other times, people will write two sentences, starting the second with “so.”
- I didn’t want to go to the party. So I went home instead.
The problem is that these two sentences are the completion of a single idea; therefore, they should be joined together following proper conjunction rules to form a compound sentence.
Conclusion
The rule of thumb with writing is not to begin a sentence with any coordinating conjunction unless used in a character’s dialogue to represent casual conversation.
It is generally accepted when used in spoken speech.
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Starting a sentence with a conjunction has long been a point of contention. Many of us have grown up with this grammatical style strongly enforced by our teachers. However, it might not be as wrong as we think. Recently, there has been a resurgence in its use with some likening it to um, and like, due to its overuse in writing. Some writers simply label it as the latest trend in writing style.
In fact, starting a sentence with a conjunction such as so, for, but can actually be totally acceptable. Most people don’t care, but those who do, care a whole lot. So, why do many people hate seeing it? Well, the main reason is that it can result in fragmented sentences, which impede flow and readability. Another reason is the fact that it can give a condescending tone to a piece of writing. But, they do have their uses (just as we used them in the last few sentences).
Roles of so
We’ll now take a look at the different ways of using the word. When not at the beginning it can simply be used as an adverb to create more intensity around an adjective like this:
That puppy is so cute.
This is very common in informal writing and should be avoided in more professional pieces. It can be used as a conjunction like this:
The puppy was cute, so I picked it up.
And then, we come to using so at the start of a sentence.
Starting with so
Often so is used in a similar way as the last example, as a conjunction, but placed at the start of a sentence;
The puppy was cute. So, I picked it up.
When you use a conjunction at the start of a sentence, it makes much more of an impact. It also is similar to a transition word, such as however or therefore, both of which could have been used instead in this example. This type of use must always see the word followed by a comma, even in the middle of sentences.
Incorrect: The puppy was cute. So I picked it up.
It should be noted though, that this is STILL not the so that annoys people despite starting a sentence. Linguists will explain that this is something called a discourse marker – a word that connects ideas in a conversational manner.
Another example of this would be:
So, how have you been?
This is not the same use as above and simply refers to information that both parties of the conversation have access to. We can also use so to come back to something mentioned earlier in a conversation:
So tell me about the puppy.
Really, what annoys people is the use of so just to start a sentence;
So, I saw the cute puppy and I picked it up.
This type of usage is more used in speech rather than writing. But if you’re aware of it, you can avoid it! Or indeed use it in your writing when writing conversations – that added bit of realism never hurt anyone.
So, here are our final words
There you have it. There are multiple ways to use so at the start of a sentence and all of them are correct. At the end of the day though, try not to overuse them as they can become annoying and even the best of us run the risk of fragmented sentences if we do so.
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What is «so» when a sentence begins with it?
It’s a discourse marker, like oh, well, now, and many others.
It can be used…
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To inform the listener that something is relevant to their interest: “So, Sam was asking about you the other day…” suggests something in the air between them, like love, tension, or a bad smell.
-
To introduce a story, explanation, or change of topic: if I ask someone “What happened on your vacation?” and they begin with “So…”, I’m going to make some popcorn.
-
To relate a statement to the existing topic, a metaphorical extension of its “therefore” sense to “considering that…” or “in light of what we’ve been discussing…”.
-
As a generic discourse marker, to take a moment to gather one’s thoughts, just like the others above.
When did it start?
It’s hard to say. (I can’t find a satisfactory source.) Formal discourse markers, such as Beowulf’s hwæt mentioned in another answer, are well attested in written records. They particularly appear in texts of the sort meant to be performed—poems, epics, songs, plays, and so on—that is, not so much in tax records and epitaphs.
So in particular has been used in roughly this way, meaning “thus”/“therefore”, for hundreds of years, since early modern English. NPR claims that the specific use of so as a discourse marker for introducing an explanation rose to mainstream infamy from about the 1980s to the early 2000s, possibly influenced by the English of Silicon Valley during the tech boom.
Is it just a «pause» word…
No, but, so, it can definitely function that way too, so, yeah.
…(and is there a word for that)?
There is! That’s a filler word, such as “um”, “like”, “er”, “ah”, and all those other little interjections. “Just” is a bit belittling: filler words serve an important pragmatic role in conversation, namely, they signal that you’re thinking or pausing but still holding the floor.
As it happens, I rarely use those kinds of filler, and as a result, I’m often met with “What?” or interrupted, because I pause without an indication that I’m not done yet, so people tend to assume I am done. They either have trouble parsing my half-sentence as a full one, or mistakenly think it’s their turn. I’m not quite following the rules for discourse dynamics, and it trips us up.
Is it grammatically correct?
Yes. It’s used and understood by native speakers of many dialects now and I’d say it forms an everyday part of informal spoken standard English.
Am I the only one that finds it annoying?
Nope, in the late aughts to early teens (when this question was originally asked) there was a spike in grumbling about this usage as it reached mainstream saturation. As always, you’re free to get annoyed by any language change you like, or rather, dislike, but it’s worth reminding ourselves that “I don’t like it” is not the same thing as “It’s bad”.