Put your foot in your mouth

tʃaɪniːzle̞tə o̞ tʃaɪniːzle̞tə ɽä se̞ ɽɯᵝ keɪ juː siː eɪtʃ aɪ əʊ ɛs juː biː iː ɑː eɪ ɛs iː ɑː juː

In Japanese 口を滑らせる (kuchi o suberaseru)

This idiom means to let something slip out of one's mouth.