H-dropping is a linguistic term used to describe the omission of initial /h/ in words like house, heat, and hangover in many dialects of English, such as Cockney and Estuary English. The same phenomenon occurs in many other languages, such as Serbian, and Late Latin, the ancestor of the modern Romance languages. Interestingly, both French and Spanish acquired new initial [h] in mediæval times, but these were later lost in both languages in a "second round" of h-dropping (however, some dialects of Spanish re-acquired /h/ from Spanish /x/). Many dialects of Dutch also feature h-dropping, particularly the southwestern variants. It is also known from several Scandinavian dialects, for instance Älvdalsmål and the dialect of Roslagen where it is found already in Runic Swedish.
It is debated amongst linguists which words originally had an initial /h/ sound. Words such as horrible, habit and harmony all had no such sound in their earliest English form nor were they originally spelt with an h, but it is now widely considered incorrect to drop the /h/ in the pronunciation.
H-dropping in English is found in all dialects in the weak forms of function words like he, him, her, his, had, and have; and, in most dialects, in all forms of the pronoun it – the older form hit survives as the strong form in a few dialects such as Southern American English and also occurs in the Scots language. Because the /h/ of unstressed have is usually dropped, the word is usually pronounced /əv/ in phrases like should have, would have, and could have. These are usually spelled out as "should've", "would've", and "could've".
The opposite of aitch-dropping, so-called aitch-adding, is a hypercorrection found in typically h-dropping accents of English. Commonly found in literature from late Victorian times to the early 20th century, holds that some lower-class people consistently drop h in words that should have it, while adding h to words that should not have it. An example from the musical My Fair Lady is, "In 'Artford, 'Ereford, and 'Ampshire, 'urricanes 'ardly hever 'appen". Another is in C.S. Lewis' The Magician's Nephew: "Three cheers for the Hempress of Colney 'Atch". In practice, however, it would appear that h-adding is more of a stylistic prosodic effect, being found on some words receiving particular emphasis, regardless of whether those words are h-initial or vowel-initial in the standard language.
Words borrowed from French frequently begin with the letter h but not with the sound /h/. Examples include hour, heir, hono(u)r and honest. In some cases, spelling pronunciation has introduced the sound /h/ into such words, as in humble, hotel and (for most speakers) historic. Spelling pronunciation has also added /h/ to the English English pronunciation of herb, /hɜːb/, while American English retains the older pronunciation /ɝb/.