Japanese has both phonetic and glyphic (hieroglyphs were used by Egyptians (hiero(s)-holy glyph(os?)-sign), the correct word is glyphic) writing, and has rather distinctive sounds that are fairly easy to transcribe to Roman letters (except for "ru" that's some kind of combination of "r" and "l").
It's worse with Chinese, which doesn't have a sign language, and has lots of sounds that are very different from those represented in the Roman alphabet.