The word "wherefore" may seem confusing to spell, but it actually follows a consistent pattern in English. The "wh" digraph is pronounced as /hw/, with the /h/ being a voiced fricative sound. The "ere" ending is pronounced as /ɛr/, a diphthong containing both the open-mid front unrounded vowel /ɛ/ and the rhotic /r/ sound. When put together, the word is pronounced as /ˈhwɛrfɔr/. Despite its archaic use in modern English, understanding the phonetic components of "wherefore" can provide insight into how spelling and pronunciation have evolved over time.
For which reason; why.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "wherefore" is a Middle English term derived from the Old English phrase "hƿǣrfore". It is a combination of the Old English words "hƿǣr" meaning "where" and "fore" meaning "for what reason" or "therefore". In modern usage, "wherefore" is often misunderstood as a question word meaning "where", mainly due to its usage in Shakespeare's play Romeo and Juliet: "O Romeo, Romeo, wherefore art thou Romeo?" However, in this context, "wherefore" actually means "why", asking why Romeo had to be who he is and come from the rival house.