Is tapping common in English?

Question

From Bruce Hayes' Introductory Phonology, I am presented with the following phonological rule called tapping:

/t/ -> [ɾ] / [+vowel] ___ [+vowel -stress]

That is, /t/ has an allophonic realization as [ɾ] (Alveolar tap) when followed by a vowel and preceded by a stressless vowel. If this is correct, then a word like city should be pronounced as /'sɪɾi/ rather than /'sɪti/.

Would failing to realize /t/ as [ɾ] in such environments sound wrong to a speaker of General American? And secondly, are there any dialects of English where tapping is known not to occur?

Answer 1

For most American English speakers, tapping (commonly called flapping) is optional. It may happen; it needn't happen. If you don't do it, the worst that could happen is that you might sound overly formal. But your tapless pronunciation would still sound like English.

I have heard that British pronunciation does not have flapping. There might very well be a number of other English dialects without flapping.

Hayes' formulation of the rule is not very good -- maybe it was just meant as a first approximation.

Answer 2

I'm a high schooler from Chicago with some sort of General American accent. Tapped realization of the /t/ and /d/ phonemes in the positions you mentioned is extremely common in American English. However, I don't think it is common at all outside North America, but there may be some accent of which I'm unaware that uses the tap. However, tapping (also called flapping) is a key feature of General American English. Use of a plosive in these circumstances in an American accent sounds gratuitously formal and somewhat nonstandard to my ears, but not necessarily wrong.

However, there are many exceptions and variations. I think the t-vowel-n combinations are pretty well known as a special case. They are commonly realized as [ʔn̩], sans tap, even following a vowel. However, this is not universal. At school, I once heard a student pronounce "Newton" with a final syllable of [ɾɪn] and then heard another student pronounce "Britain" ending with [tʰɪn] (I'm not certain if he aspirated the plosive or not). This was noticeable to me since neither used the common pronunciation that I usually use, [ʔn̩].

On the other hand, there are cases in which the tap is used that do not follow a vowel. For example, I pronounce "forty" as something like [ˈfɔɹ̈ɾi]. Thus, I think the rule you mentioned may also apply when following a rhotic approximant. There may be even more situations in which the tap is used, but I cannot think of them currently.