[1] Variation between both dental and alveolar forms exists in much of the working-class English speech of North America and sometimes southern England.
It is also common for babies and toddlers, who are still learning to talk and/or haven't fully grown their front teeth capable of producing the Th sound.
The /t-θ/ opposition may be lost, exceptionally in the environment of a following /r/ (making three homophonous with tree), and in the case of the word with, (so that with a may rhyme with the non-rhotic pronunciation of "bitter-bidder"; with you may be [wɪtʃu], following the same yod-coalescence rule as hit you.
[citation needed] In African American Vernacular English, in the words with and nothing, [t] may occur corresponding to standard [θ], with the [t] itself being succeeded by the t-glottalization rule: thus [wɪʔ] for with and [ˈnʌʔɪn] for nothing.
Th-stopping is also commonly heard, specifically from speakers of working-class origins, in the American English dialects of the Inland North (for example, in Milwaukee, Chicago, Cleveland, Buffalo, and Scranton), the Upper Midwest (for example in the especially Fennoscandian-descended locals of Minnesota's Iron Range and Michigan's Upper Peninsula), and the Mid-Atlantic region (for example, in Philadelphia and Baltimore),[4] It is also heard in a minority of speakers of England's Estuary dialect (for example, in London), but only in the case of word-initial /ð/.