How to say "hmm" in Japanese

• ふんCommon
  interjectionThe everyday 'hmm' of pondering or skepticism: a low grunt made while considering what someone said, or when unconvinced. It also covers 'humph' and a doubtful 'huh'.
  「じつは自由じゆう研究けんきゅうで相談そうだんしたいことがあって・・・」「どれ・・・。ふーん、被子植物ひししょくぶつについて調しらべてるのね」↗

  "Well, there's something I'd like your advice on about my research project ..." "Let's see... Hmm, you're investigating flowering plants then."
• ふむ
  interjectionA thoughtful 'hmm' that shades into 'I see': the sound of someone mulling over information and half-acknowledging it. Less common than ふん, with a pondering, deliberative flavor.
  「ふむ」 武田たけだ先生せんせいは口くちひげを捻ひねりながらうなった。↗

  "Hrmm," mumbled Professor Takeda as he twisted his moustache.
• むむ
  interjectionAn onomatopoeic interjection for a humming 'hmm' of pondering. It is only a marginal way to render 'hmm'; in ordinary speech ふん or ふむ is usually the word you want.
• ほーん
  interjectionA colloquial, drawn-out 'hmm' or 'hum' suggesting a vague, half-attentive reaction — closer to 'huh?' or a noncommittal 'um, OK ...' than to serious pondering.
• あっそ
  interjectionNot a pondering 'hmm' at all: this is the curt 'oh, OK' or 'oh, yeah?' of someone brushing information off, so as 'hmm' it reads as dismissive or uninterested.
  「あっそ」と流ながすのもよし、本気ほんきにするのもよし。↗

  You can let it slide with a "oh?" or you can take it seriously.

For a thoughtful or skeptical 'hmm' use 「ふん」, for an acknowledging 'hmm, I see' 「ふむ」; 「むむ」 is marginal, 「ほーん」 a drawn-out colloquial murmur, and 「あっそ」 a curt, dismissive reaction.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• ふんhmm
• ふむhmm
• むむhum
• ほーんhuh?
• あっそoh, OK
• さあwell
• かhmm