In Eastern Catalan (except Majorcan), unstressed vowels reduce to three: /a e ɛ/ > [ə]; /o ɔ u/ > [u]; /i/ remains distinct. There are a few instances of unreduced [e], [o] in some words. Alguerese has lowered [ə] to [a].
Is there an answer to this question (If it cannot be answered, say "unanswerable"): Which vowel remains distinct?
/i/