Meaning of “Yatte mouta(やってもうた)”
“Yatte mouta(やってもうた)” means “I screwed up!” or “I made a mistake”.
“Yatte mouta(やってもうた)” is Kansai dialect and it’s same with “YatteSimatta(やってしまった)” or “Yacchimatta(やっちまった)”.
“mouta(もうた)” is ending of a word in Kansai area.
In Japan, some people use Kansai dialect if they are not from Kansai area. Because Kansai area is famous for “Owarai(お笑い)” which means comedy.
So some people use Kansai dialect to make sounds funny.
We have a stereotype “Every Kansai people must be fun people”.
Example Conversation
A: Why didn’t you join the online drink party yesterday? Your crush “Kasumi-chan” also joined.
B: What? I don’t know… what is it???
A: Do you check LINE group??
B: No, I don’t… Yattemouta(やってもうた)…
A: お前なんで昨日オンライン飲み会参加しなかったの?お前の好きなかすみちゃんも参加してたよ。
B: え?なにそれ?
A: ライングループ見てる?
B: 見てない・・・ やってもうた・・・。