The glottal fricative

The glottal fricative /h/ is produced with sufficient friction in the glottis to be classified as a glottal sound. It is never voiced, and is best explained as a whisper. It only occurs in a pre-vocalic position, i.e. in front of a vowel or diphthong. The position of the vocal organs is determined by the following vowel/diphthong. From the point of view of production, the glottal fricative could be regarded as the unvoiced onset of the following vowel.