ᴍᴏᴜᴛʜ vowel phoneme /aʊ/
The ᴍᴏᴜᴛʜ vowel phoneme /aʊ/ is an English vowel phoneme consisting of the vowel sound used by English speakers in its keyword mouth. It’s a ʊ-closing diphthong. It’s represented in broad notation as /aʊ/.
Words from the ᴍᴏᴜᴛʜ lexical set are pronounced with this phoneme.
In reference accents, this is pronounced as a diphthong. In RP and Gen Am, the diphthongal nucleus is the open front unrounded vowel sound [a], and the diphthongal glide is the near-close near-back rounded vowel [ʊ].