From Teflpedia

Wh is an English consonant digraph formed of the letters W and H.

Wh forms the start of wh- words but not all words beginning WH are wh- words. It generally represents a voiced labio-velar approximant /w/ but can also represent an unvoiced glottal fricative /h/. A common non-standard pronunciation following the wine-whine split sees wh pronounced as an unvoiced labialised velar approximant.

As /w/[edit | edit source]

This is the default; words in this group can be subject to the wine-whine split.

  • what, when, which, white, why, etc

As /h/[edit | edit source]

With /w/ as the default, certain words need to be memorised as beginning with /h/:

  • who, whom, whose, whole (adv - wholly, and compounds such as wholesome).

Less common words:

  • whore, whooping (as in whooping cough, whooping crane).

Across syllable boundaries[edit | edit source]

Wh can also occur across syllable boundaries, in which case it is not a digraph. For example, knowhow is a compound of know+how.