Diphthongs

In phonetics, a diphthong (Greek δίφθογγος, "diphthongos", literally "with two sounds," or "with two tones") is a vowel combination in a single syllable involving a quick but smooth movement or glide from one vowel to another, often interpreted by listeners as a single vowel sound or phoneme. While "pure" vowels, or monophthongs, are said to have one target tongue position, diphthongs have two target tongue positions.

If you want to know more about diphthongs click on it. and you will see nice pictures explaninig the positions of these.

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