I'm not sure how it's implemented exactly, you'd need to go browse the amethyst repo for that, but I've tested it on some japanese names and it works pretty well. It's a robotic voice so it's not natural but the pronounciation is not american. It actually pronounces the hiragana and katakana.
Discussion
ok, transliterating japanese alphabetical symbols isn't that hard to do but what if i give it кирилица? like молоко или хорошо или покажи мне любов