Can you use a mix of English Japanese and French cards in Yu-Gi-Oh?

Answer

"Of course you can if you are trilingual but you will be thrown out of a tournament if you tried to enter.

In a fun duel, yes you can. In a regulation tournament, the only cards you can use are English and Spanish. "

That statement is 100% false. You may use as many foreign language cards in your deck so long as they are not OCG (korean, chinese, japanese, or any other oriental language) so long as you have a ready translation next to you. This means you could have french, english, spanish, and portuguese in your deck if you have translations ready.