In My Hero Academia we see that when Midoriya is mumbling they use ブツ to symbolize it. Is this the rule for anime/manga/japanese or does it only happen in My Hero Academia?
-
Cross-posted on Japanese.SE: Is there an onomatopoeia of mumbling in japanese? – Aki Tanaka♦ Jun 10 '18 at 15:30
ブツブツ or ぶつぶつ (the same word, just in katakana vs hiragana) is a standard Japanese onomatopoeia for mumbling, muttering, or grumbling to oneself. This list of Japanese onomatopoeia includes ぶつぶつ in it, along with many other onomatopoeia that show up in manga.