In standard English, the digraph th is a dental fricative [θ, ð]. Several dialects feature th-fronting, where th becomes a labiodental fricative [f, v]; others feature th-stopping, where th becomes a dental stop [t̪, d̪]. For example, three sounds like free with th-fronting, tree with th-stopping.
How well can English speakers distinguish word pairs in these dialects? Specifically:
- Can th-modifying speakers distinguish /f–θ/ and /t–θ/ in their own dialects?
- Can they distinguish minimal pairs as spoken in standard English?
- Can standard English speakers distinguish the th-modified variants from similar words?
I expect that the answers vary between dialects and individuals, so I'm interested in reasonable generalizations. If there's a significant difference between (for example) th-fronting in Cockney and African American Vernacular English, I'd be interested in that too. Likewise if there's a significant difference between the voiced and unvoiced consonants.
Wikipedia notes that th-stopping dialects generally distinguish between the dental stop of thanks [t̪æŋks] and the alveolar stop of tanks [tæŋks], but they lose the /t–θ/ opposition in some cases like tree/three, and the /d–ð/ opposition is even weaker. This answers part of the question for th-stopping dialects: They can sometimes (but not not always) distinguish /t–θ/ in their own dialect, and I imagine they can also hear the opposition in standard English. I'm not sure whether a typical speaker of standard English could distinguish [t̪æŋks] from [tæŋks], however.
One case that particularly interests me is whether th-fronting speakers can distinguish the /f–θ/ opposition in standard English. When I say the minimal pair free–three /fɹi–θɹi/, can th-fronting speakers hear the difference, or is [f–θ] an allophone in free variation for them?
Examples of standard English minimal pairs that might merge in these dialects:
- father/fava, mother/mutter
- thin/fin, thin/tin
- three/free, three/tree
- with/whiff, with/wit
- wraith/Ralph, wraith/rate