nhất ngôn ký xuất, tứ mã nan truy

== Vietnamese == === Etymology === Sino-Vietnamese word from 一言既出，駟馬難追 (“A word once spoken cannot be overtaken by a four-horse-team.”) === Pronunciation === (Hà Nội) IPA(key): [ɲət̚˧˦ ŋon˧˧ ki˧˦ swət̚˧˦ tɨ˧˦ maː˦ˀ˥ naːn˧˧ t͡ɕwi˧˧] (Huế) IPA(key): [ɲək̚˦˧˥ ŋoŋ˧˧ kɪj˨˩˦ swək̚˦˧˥ tɨ˨˩˦ maː˧˨ naːŋ˧˧ ʈwɪj˧˧] (Saigon) IPA(key): [ɲək̚˦˥ ŋoŋ˧˧ kɪj˦˥ s⁽ʷ⁾ək̚˦˥ tɨ˦˥ maː˨˩˦ naːŋ˧˧ ʈ⁽ʷ⁾ɪj˧˧] Phonetic spelling: nhất ngôn ký xuất tứ mã nan truy === Idiom === nhất ngôn ký xuất, tứ mã nan truy a word once spoken cannot be taken back; a promise must be kept; a promise is a promise 2019, An Nguyên, "Nhất ngôn ký xuất", Thanh Niên (Young People) Online