from Latin sermōcinat-, pa. ppl. stem of sermōcinārī, from sermo talk, discourse, speech
1623 - The English Dictionarie, or an Interpreter of hard English Words, Henry Cockeram;
"Sermocinate, to talke, to commune"
From: Mother Red Cap
Copy of a Letter from Henry Foxall, Gentleman, to Charles Firebrace, Esquire
From my Chambers in Whitehall, this 13th September, 1666