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:[2][3]So graunte hem sone out of this world to pace (So grant him soon out of this world to pass);So as a sentence opener has been used in later historical literary works such as:[2] 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.'"
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.
[9] "So" may refer back to something previously mentioned, such as:[10] Other possibilities include: 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.
[1][14] Examples of dangling "so": "So" may close a sentence as an intensifying adverb, such as in "I love her so".