Th-fronting is the pronunciation of the English "th" as "f" or "v". When th-fronting is applied, [θ] becomes [f] (for example, three is pronounced as free) and [ð] becomes [v] (for example, bathe is pronounced as bave). (Here "fronting" refers to the position in the mouth where the sound is produced, not the position of the sound in the word, with the "th" coming from the tongue as opposed to the "f" or "v" coming from the more-forward lower lip.) Unlike the fronting of [θ] to [f], the fronting of [ð] to [v] usually does not occur word-initially (for example, while bathe can be pronounced as bave, that is rarely pronounced as *vat) although this was found in the speech of South-East London in a survey completed 1990-4. Th-fronting is a prominent feature of several dialects of English, notably Cockney, Essex dialect, Estuary English, some West Country and Yorkshire dialects, African American Vernacular English, and Liberian English, as well as in many non-native English speakers (e.g. Hong Kong English, though the details differ among those accents). Do we really pronounce "th" https://youtu.be/wDdtdeHZ4pI Papa Teach Me English