Colloquial contraction of だろう into ろ after past tense verb (e.g. 言ったろ)

Question

I noticed in many anime I watched that 「言っただろう」 is often contracted into 「言ったろ」 in conversations between friends and families. I'm guessing this contraction is both colloquial and standard (as in, everyone understands it).

But I'm wondering if this contraction of 「だろう」 is limited to the phrase 「言っただろう」 only. Is there any instance where 「だろう」 gets contracted before other past tense verbs than 「言った」, e.g. 来たろ?

Answer 1

I'm not sure that this is a contraction of 言っただろう, actually, I would interpret it as a contraction of 言ったろう -- which has the same meaning as 言っただろう, but is now archaic or at least very old-fashioned, I think (alas).

• "僕の感覚が鋭敏なことは前に言ったろう？" = "Said I not that my senses were acute?" (from Sasaki Naojiro's translation of "The Fall of the House of Usher")

(Note: It is possible that the evolution was not direct, and 言っただろう/言っただろ were indeed intermediate steps. I don't have any evidence either way, just Occam's Razor.)

Anyway, the ろ ending can be applied to any verb in theory.　笑ったろ, 喰ったろ, etc. But be careful not to confuse it with the "-たろ" or "-たろう" that actually mean "-てやろう" -- totally different ending!