Always loved the "Battle royale" anime, but am curious about why in the Japanese title it's「ロワイアル」.
Shouldn't it be something like「ローヤル」, if you wanted to match the French pronunciation? Why the「ワ」?
(I know royal is「ロイヤル」)
Pretty simply, because there's a /w/ in the French royale /rwajal/. The onset cluster /rw/ is not allowed in Japanese phonotactics, so one of two repair strategies must be used:
In Japanese loanword phonology, both strategies are used, but epenthesis is much more common. The vowel /o/ is inserted between /rw/ and the result is ロワ.