Dipthongs are produced by varying local tract, ch, th, pl, sn, st, as 
vowels by excited local tracts
eg. a, e, i, o, and u 
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Diphthong is a vowel sound in which the tongue changes position to produce the sound of two vowels.
Example: sh, ch, th, pl, sn, st, as 

Vowel is a speech sound produced by humans wen the breath flows out through the mouth without being blocked by the teeth, tongue,etc.  

Example: a,e,i,o,u
1 5 1
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