Flaming in another language

Well I just got teamed up with an enraged person which flamed hard from the beginning, but he was flaming in german. Normally I'd guess that Riot Bots translate the chat to english but he made so many mistakes so there is no chance a bot can translate it. I just reported him, stating that he was flaming in german and translated some of his flame into english, but is this sufficient? How does Riot handle flame in other languages?
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