The Aspirates

• The phoneme /h/ is often compared with the schwa /&/ because of the extreme acoustic variability of both of these phonemes, which have radically different realizations depending on their context.
• The aspirate /h/ occurs only in syllable-initial position in English, usually preceding a vowel. Some speakers also use the aspirate before /w/ in all of the wh-words such as when and where. This combination was originally spelled `hw' in Anglo-Saxon.
• The phoneme /h/ is similar to the fricatives, since the source of its energy is turbulence caused tight constriction of an articulator. But unlike all of the fricatives which we have covered, the obstruction for /h/ is not in the vocal tract, but rather in the glottis itself: the vocal cords are held together more tightly than for an open sound such as a vowel, so that there is continuous turbulence which emerges from the mouth at the resonant frequencies formed by the other articulators. This sort of turbulence is called aspiration rather than frication. The resonant frequencies of the aspiration depend on the configuration of the vocal tract, spanning the entire speech spectrum. Since /h/ is normally pronounced before a vowel, the resonant frequencies will be those of the succeeding vowel, especially in the latter stages of the /h/. Preceding /w/, all energy is very low. In whispered utterances, aspiration is used to produce all of the voiced phonemes of English; the voicing is replaced by bands of aspiration.
• Like the other fricatives, /h/ can be partly voiced, but this is not a phonemic distinction in English. Rather, /h_v/ is an allophone of /h/ which occurs primarily in intervocalic position. Look for a less coherent pattern than normally present in voicing, something midway between voicing and aspiration, coming from a mixture of glottal pulses and aspiration. See Figure 3 for two examples of /h/.