thfronting

Thfronting is a phonological process observed in some dialects of English, particularly in children's speech and certain regional accents. It refers to the substitution of the voiceless dental fricative /θ/ (as in "thin") with the voiceless labiodental fricative /f/ (as in "fin"), or the voiced dental fricative /ð/ (as in "this") with the voiced labiodental fricative /v/ (as in "vis").

For example, a child might say "fink" instead of "think," or "dat" instead of "that." Similarly, in some accents, words like "three" might be pronounced as "free," and "breathe" as "breeze." This process is a common developmental stage for young children learning to speak as they simplify complex sounds. It is also a characteristic feature of some established dialects, where it is considered a standard pronunciation rather than a speech error.

The prevalence of thfronting can vary geographically and socioeconomically. While it is considered a typical pronunciation in certain areas, it may be perceived as non-standard or even incorrect by speakers of other dialects. The exact reasons for its occurrence are debated, but it is generally attributed to the articulatory ease of producing /f/ and /v/ compared to /θ/ and /ð/, which require the tongue to make contact with the teeth.