With a few exceptions, Pokemon can say only their own names, but that name varies depending on which language you're playing your game in. This poster highlights some of the alternate Pokemon names from around the world.
Artist James Chapman usually posts cartoons comparing onomatopoeias in various languages—and sells them as posters on Etsy. Here, he turns his attention to Pokemon. If you're curious about other international Pokemon names, you can see the lists of Japanese, German, French, Korean, and Chinese names at Bulbapedia.