pure vowel,diphthongs

最新上市德国vowel2.1升级版蓝牙音响可插u盘sd卡带遥控重低音
short vowels - learn to read
twelve pure vowels ( monophthongs) / i:, i, e, 82, 88, 89 :, 88
vowels: front vowels & central vowels
of sounds, students can be independent learners 12 pure vowels