Sfoot = God's foot. Predates even us!
https://en.wiktionary.org/wiki/%27sfoot

Growing up as a child in the south of England in the 60s I heard this a lot. Often accompanied with "Gaw", "Gaw Blimey!". There's a bit of cockney dialect there. I've always taken this to originate from "God Blind Me!" i.e. "God blind me if this isn't" somethi...

Thanks Apo, thanks AlphaDictionary. Geoffrey Sampson should be here, or maybe he is. A very nice overview and just the sort of lead I've been looking for. The question of language complexity seems to me to remain open. Language cannot have started fully formed, so must have initially increased in co...

People have deduced a lot of the history of words, but I haven't found anything about the history of grammar. What was the grammar of PIE like? Grammar seems to get simpler over time. How did the earlier complex grammars come about from presumably the very simple grammars used with man's first grunts?