So is an English word that, apart from its other uses, has become increasingly popular in recent years as a coordinating conjunctive opening word in a sentence. This device is particularly used when answering questions although the questioner may also use the device. So may also be used to end sentences. When ending a sentence, it may be: a coordinating conjunctive to refer backwards to something previously mentioned a coordinating conjunctive dangling "so" (sometimes called trailing "so")So What? What it means when people leave the word “so” dangling at the end of a sentence The Atlantic Julie Beck 26 Aug 2015 to refer forwards to something that may be said an intensifying adverb.
Sentence opener The first known written use of so as a sentence opener is in several lines of Chaucer's Troilus and Criseyde, published in the mid-1380s, for example:
So as a sentence opener has been used in later historical literary works such as: The Rape of Lucrece, 1594, by William Shakespeare Pamela: or, Virtue Rewarded, 1740, by Samuel Richardson
It is widely believed that the recent ascendancy of so as a sentence opener began in Silicon Valley. Michael Lewis, in his book The New New Thing, published in 1999, noted that "When a computer programmer answers a question, he often begins with the word 'so. Microsoft employees have long argued that the "so" boom began with them.Origins of using "so" as a sentence opener Boing Boing Mark Frauenfelder 17 June 2010
Purpose Various suggestions have been made as to its purpose: as a coordinating conjunctive to refer backwards to something previously mentioned as a discourse marker to signal that the following words are chosen for their relevance to the listener to provide a small amount of extra thinking time
In his Modern English translation of Beowulf, Irish poet Seamus Heaney uses "So" to translate the single-word opening line, Hwæt! (also rendered 'lo', 'hark', 'listen', etc). He explains that "in Hiberno-English Scullion-speak [...] '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".
Sentence closer Referring back "So" may refer back to something previously mentioned, such as:Oxford Dictionaries "If she notices, she never says so." Speaker 1: "Has somebody called an ambulance?" Speaker 2: "I believe so."
Other possibilities include:
Dangling so A dangling "so" in conversation invites the listener to articulate or consider the implications of the information provided without the speaker having to articulate it himself or herself.So… why is everyone saying “so?" USA Today Haley Goldberg 14 Feb 2014It's Okay To End Your Sentences With 'But' Or 'So,' Right? The Huffington Post 15 May 2014 Claire Fallon It has been interpreted as sometimes a form of bragging.People who end sentences with 'so': Yes, they're bragging Crain's Chicago Business Lisa Bertagnoli 15 May 2010 A dangling "so" in conversation may be represented in text as "so" followed by an ellipsis: "...".Why do people end sentences with “so”? What effect does it have on conversation? Dictionary.com Jane Solomon 21 Aug 2013 Examples of dangling "so": "Yeah, it's pretty exciting, though we're not really sure whether it will work out, so..." Speaker 1: "How was your date?" Speaker 2: "Well, he didn't show up, so..."
Intensifying adverb "So" may close a sentence as an intensifying adverb, such as in "I love her so". "So" in the middle of a sentence can also be an intensifying adverb, such as in "I so love her".
See also Discourse marker Filler (linguistics)
References
Further reading
So, here's a carefully packaged sentence that shows me in my best light The Guardian Oliver James 26 Jul 2013