The only languages that he's become even somewhat competent at are the ones closely related to languages that he already knew.

Here's a video of him "holding a conversation" in Mandarin: https: https://youtu.be/hoWXYmLpNJY?t=643

It's a series of non-stop "uh-huh's" and, frankly, it's embarrassing. He's a marketing gimmick and pretty reviled by the polyglot community for trivializing how much effort learning a language actually takes.