Sentences beginning with "so"?

This also came up on either a BBC or CBC science program, but not as a linguistically-oriented discussion.

Over the last two or three years I've noticed a lot more people starting a sentence with "so": "so when we take the ...", "so I have this ...", "so the basic idea ..." and (uh) so on.

What is "so" when a sentence begins with it? When did it start? Is it just a "pause" word (and is there a word for that)? Is it grammatically correct? Am I the only one that finds it annoying?

Edit: Much of its usage in scientific discussions is as a "therefore".

Solution 1:

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…

• 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”.

Solution 2:

So is supposed to be used in something like, "The grass is tall, so it will be mowed." The use expanded to "The grass is tall. So, it will be mowed."

Now, so is commonly used at the beginning of a sentence to mean "as a result" as it was traditionally used, but also with the same meaning as "uh," as an initial attention-getter. For example, "So, do you want to go get some lunch?"

It is also used sometimes in a discussion to "hold the floor," or keep one's side of the conversation going by making some noise between sentences. This is particularly common in public interviews.

So is sometimes used in the beginning of a sentence to connect the sentence with the previous sentence or paragraph, as a discourse marker. It may imply that the content of the sentence is there because of the previous idea, or it may just be there to keep up the rhythmic flow of the text.

So, I find it annoying, too.

Solution 3:

It's partly a regional usage: Seamus Heaney in the foreword to his translation of Beowulf says

Conventional renderings of hwæt, the first word of the poem, tend towards the archaic literary, with ‘lo’, ‘hark’, ‘behold’, ‘attend’ and – more colloquially – ‘listen’ being some of the solutions offered previously. But in Hiberno-English Scullion-speak, the particle ‘so’ came naturally to the rescue, because in that idiom ‘so’ operates as an expression that obliterates all previous discourse and narrative, and at the same time functions as an exclamation calling for immediate attention. So, ‘so’ it was:

So. The Spear-Danes in days gone by and the kings who ruled them had courage and greatness. We have heard of those princes’ heroic campaigns.

(full text here; http://www.wwnorton.com/college/english/nael/beowulf/introbeowulf.htm)