What’s the meaning of...?

Consonant

A basic speech sound in which the breath is at least partly obstructed and which can be combined with a vowel to form a syllable.

Vowel

A speech sound which is produced by comparatively open configuration of the vocal tract, with vibration of the vocal cords but without audible friction, and which is a unit of the sound system of a language that forms the nucleus of a syllable.

Diphthong

A sound formed by the combination of two vowels in a single syllable, in which the sound begins as one vowel and moves towards another (as in coin , loud , and side ).