It seems to me that there is serious confusion with the "you" in this entry. For starters, this imperative form for the verb tell is saying it, and the "you", in the best of cases, would be a majestic plural, otherwise the pronoun is "you". "Say it for" conjugation (without accent, of course) is used when the vosear, finally say that it is not incorrect, but an idiom with its own rules, although different from the traditional, very common Spanish in the Rio de la Plata and parts of the Caribbean. See that it is the boseo.
