Phonological history of English consonants

The voiceless stops /p/, /t/, /k/ are typically aspirated when they begin a stressed syllable, becoming [pʰ], [tʰ], [kʰ], as described under English phonology (obstruents).

[1] In certain accents, such as Geordie (among younger women)[2] and in some speakers of Dublin English,[3] /p/, /t/ and /k/ can be preaspirated when they come at the end of a word or utterance, becoming [ʰp], [ʰt], [ʰk].

Apart from the T-voicing that results from flapping (described above), some dialects feature other instances of voicing or lenition of the stops /p/, /t/ and /k/.

For details, see T-glottalization, as well as English phonology (obstruents) and glottalization in consonant clusters.

If all final voiceless stops are glottalized, as may occur in some London speech, then sets of words such as lick, lit and lip may become homophones, pronounced [lɪʔ].

It is common in many dialects, especially in England, Wales, Australia and Jamaica, but is generally stigmatized, and is not a feature of the standard accents.

A /x/ is more commonly heard, especially in the Celtic countries but also for many speakers elsewhere, in the word loch and in certain proper names such as Buchan.

In Early Middle English, partly by borrowings from French, they split into separate phonemes: /f, v, θ, ð, s, z/.

After the Middle English period, a fourth voiced fricative, /ʒ/, developed as a phoneme (alongside the voiceless /ʃ/).

[8] Some such pronunciations have spread from these dialects to become standard usage: the words vane, vat and vixen all had initial /f/ in Old English (fana, fæt, fyxen).

In parts of the west and southwest of England, initial /w/ may be dropped in words like wool and woman; occasionally, though, a /w/ may be inserted before certain vowels, as in "wold" for old and "bwoiling" for boiling.

This is common (alongside [ɹ]) in Scotland, and is also found in certain other accents, chiefly in positions between vowels or between a consonant and a vowel – this occurs, for example, in some Liverpool English and in some upper-class RP[20] (this should not be confused with the tap pronunciation of /t/ and /d/, found especially in North America).

A relatively recent innovation in the southeast of England, possibly originating from Cockney, is the use of a labiodental approximant, [ʋ], for /r/.

[22] Also in AAVE and some southern American accents, L-dropping may occur when the /l/ sound comes after a vowel and before a labial consonant in the same syllable, causing pronunciations like /hɛp/ for help and /sɛf/ for self.

[24] In some modern English accents, significant pre-L breaking occurs when /l/ follows certain vowels (/iː/, /uː/, and diphthongs ending [ɪ] or [ʊ]).

This may cause reel to be pronounced like real, and tile, boil and fowl to rhyme with dial, royal and vowel.

The preceding length of the vowel is maintained when the final obstruents are devoiced in AAVE: [bɪːk] and [bæːt] for "big" and "bad".