to speak very softly or quietly, usually to avoid being overheard by others who are nearby

ささやく, 囁く

to speak in a low, soft voice, often in a way that is difficult to hear or understand

呟く, ささやく

to speak in a low or unclear voice, often so that the words are difficult to understand

もごもご言う, ぶつぶつ言う

to repeat or perform something again, often to make it clearer, better, or to emphasize specific points

反復する, 繰り返す

to say a word or words incorrectly, especially with regards to the proper pronunciation

誤って発音する, 間違って言う

to talk rapidly and incoherently, making it hard for others to understand what is being said

支離滅裂に話す, 夢中になって話す

to release a long deep audible breath, to express one's sadness, tiredness, etc.

ため息をつく, 息を吐く

to speak with involuntary repetitive sounds or interruptions in the flow of speech

どもる, つまずく

