Why isn't the word for triangle トラヤングル?


What's the phonetic difference between toraianguru (トライアングル, the correct word
in Japanese) and torayanguru (トラヤングル)? Do they both sound the same and it's
purely a matter of orthography, or is there some deeper difference?




In short, they don't sound the same:
[ト]{to}[ラ]{ra}[イ]{i}[ア]{a}[ン]{n}[グ]{gu}[ル]{ru} sounds closer to the
pronunciation of the English source term. The `/aia/` vowel combination (as
`/a i a/`) makes a clear analog of the English `/aia/` pronunciation (as `/aɪ
æ/` for the `i` and `a` in the middle of _tr **ia** ngle_).

Meanwhile, [ト]{to}[ラ]{ra}[ヤ]{ya}[ン]{n}[グ]{gu}[ル]{ru} has no `/ai/` combination
at all, and doesn't sound as close to the English term.

(Musings: rather than [ト]{to}[ラ]{ra}[ヤ]{ya}[ン]{n}[グ]{gu}[ル]{ru}, a closer
phonetic match might be [ト]{to}[ラ]{ra}[イ]{i}[エ]{e}[ン]{n}[グ]{gu}[ル]{ru}.)

