What was the first mainline Pokemon game that had the ability to change the game language?

Question

Don't question my curiosity....

Comments

I believe it was XY, not 100% sure though.

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I think so too but I'm not sure

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Did a bit of research, and couldn’t find a clear-cut source, but multiple Reddit posts and a GameFAQs question stated that XY were the first. I would definitely answer if I found a more reputable source.

Answer 1

All copies of [X and Y] are playable in all seven of the languages that the Pokémon games are released in: Japanese, English, German, Spanish, French, Italian, and Korean.

Bulbapedia

This is the first time this phrase appears on a mainline series game. Coupled with my own experience, it's safe to say X and Y were the first to let you play in any of the available languages.