Richard A wrote:
But even German does not use "So" at the beginning to a reply to an information question. A. Wo wohnen Sie? B. *So ich wohne / or / * So wohne ich in Stuttgart. In either case, "so" would sound totally superfluous and gratuitous.
It's not a question of proper grammar that people (including myself) use so. It's a bit of American colloquialism. A bit of casual speaking and by no manner meant to be formal or academic.
It's a better alternative than um or uh, etc.... I also like to use it in writing in casual posts in various social media and forum activity. It's a verbal and written habit I like as a ... I guess quirk to my style of writing and speaking.