What "...しもーたん" could mean?


I came up with this sentence while reading manga:

何であんなふうに育ってしもーたん。

**Context:** That's what the grandfather says after his grandson exits the
house without telling anyone.

育って - I believe it's the te-form of the verb 育つ, which means (from Jisho.org):

  1. to be raised (e.g. child); to be brought up; to grow (up)

I don't know what "しもーたん" is. But from my research I gathered that しも could be
[a grammatical element in archaic
Japanese](https://japanese.stackexchange.com/questions/44663/what-is-the-
meaning-of-%E3%81%97%E3%82%82) (a sort of intensifier similar to _nothing but,
even, necessarily, etc_ ) and looking at Jisho.org, たん could be an honorifc
but that doesn't make sense since there is no character called しも.

My second guess is that しもーたん could be a contraction for something else, which
I cannot guess.




しもーた is a variant of しもうた, which is a Kansai dialectal version of しまった used
with an undesirable outcome. See the links posted by broccori. ん at the end of
the sentence is [explanatory-の/ん used to seek
clarification](https://www.wasabi-jpn.com/japanese-grammar/question-markers/).
This type of sentence-end の commonly turns to ん in casual western speech
(e.g., 好きなの? → 好きなん?).

> 何であんなふうに育ってしもーたん。  
>  = 何であんな風に育ってしまったの？
>
> Why did he grow up like that?




しもーた is a variant of しもうた, which is a Kansai dialectal version of しまった used
with an undesirable outcome. See the links posted by broccori. ん at the end of
the sentence is [explanatory-の/ん used to seek
clarification](https://www.wasabi-jpn.com/japanese-grammar/question-markers/).
This type of sentence-end の commonly turns to ん in casual western speech
(e.g., 好きなの? → 好きなん?).

> 何であんなふうに育ってしもーたん。  
>  = 何であんな風に育ってしまったの？
>
> Why did he grow up like that?

