Colloquial contraction “出しゃ[あ]”


I encountered this sentence.

> なめんなよ。てめえみていな雑魚、おれが本気をだしゃあ…

I believe the context is quite obvious: The speaker feels stronger than his
enemy, the listener. From how I understand it, I’d translate the sentence
something like this:

> Don’t make fool of me! Against a small fry like you, I don’t even need to
> fight seriously.

Still, I can’t figure out, how the ending works to carry this meaning. My
guesses so far are:

  * The trailing あ is just an emotional prolongation – the verb form is just 出しゃ.
  * The しゃ is some kind of contraction like e. g. なきゃ. But what of? Perhaps something like 出しては?

If these guesses are correct, there is probably still a part of the sentence
missing as an ellipsis.

Thus, my question is: What are the missing or contracted parts and how do they
form the meaning inferred from the context? Or maybe I got it completely wrong
and the sentence means something else?




出しゃあ is a contraction of 出せば. Compare すれば → すりゃ, 書けば → 書きゃ, 死ねば → 死にゃ, ...,
that is //eba// → //ʲa//.

The extra あ could be seen as a lengthening to compensate for the lost mora.
(See also [手えふった - what is the "え”
here?](https://japanese.stackexchange.com/q/25600/1628))

Of course it means something like

> おれが本気をだせば...  
>  If I were to get serious...

* * *

P.S. 出しては would usually contract to 出しちゃ




出しゃあ is a contraction of 出せば. Compare すれば → すりゃ, 書けば → 書きゃ, 死ねば → 死にゃ, ...,
that is //eba// → //ʲa//.

The extra あ could be seen as a lengthening to compensate for the lost mora.
(See also [手えふった - what is the "え”
here?](https://japanese.stackexchange.com/q/25600/1628))

Of course it means something like

> おれが本気をだせば...  
>  If I were to get serious...

* * *

P.S. 出しては would usually contract to 出しちゃ

