Are the phonemes [i] and [i:] "allophones" of the phoneme [ɪ] in General American?

Question

Are the phonemes [i] and [iː] "allophones" of the phoneme [ɪ] in General American? Why does the phoneme [ɪ] sound like [i] or [iː] in some words?

Example words: it x sink.

The phoneme [ɪ] sounds different in these words.

Answer 1

In the specific context of words like sink, [i] (or [iː]) and [ɪ] might be allophones for some speakers (but not for all).

This is because in this context, before the velar nasal consonant sound [ŋ], English does not regularly contrast [ɪ] and [i], and some speakers use a vowel quality closer to [ɪ] and others use a quality closer to [i]. I think it's often hard though for speakers to notice that there are other speakers who use the other vowel quality: I feel that I use [ɪŋ] and I don't think I hear [iŋ] much at all, but other people report saying and hearing [iŋ] and don't seem to notice that there are in fact speakers who use [ɪŋ].

Dictionary transcriptions use /ɪŋ/ practically universally, I think, which may obscure the existence of the [i] pronunciation. I think that [iŋ] occurs mainly in American English; I'm not sure if it occurs for British English speakers.

In most contexts, [i] and [ɪ] are not allophones: there are many contrasting pairs such as beet and bit or seen and sin.

Another context where [i] and [ɪ] do not contrast for many American English speakers is before [r], as in sear or Sirius: dictionary transcriptions tend to use [ɪr] (or [ɪɹ]), or in some cases [ɪər] (or [ɪəɹ]), but some speakers use, or feel they use, a quality more like [iɹ].

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Even in the case of words like sink or sear, the existence of variation between [i] and [ɪ] and the lack of contrast for some or all speakers doesn't necessarily imply that [i] is an allophone of [ɪ]. It would only be an allophone for speakers who feel that the vowel in sink has the same identity as the vowel in it. Some speakers who use [i] in sink, king and the like identify this vowel sound with the [iː] found in seen. For these speakers, sink and it contain two different vowel phonemes, not different allophones of the same phoneme.

Answer 2

Two sounds are said to be allophones of one another if the contrast between them is never semantically significant. So a "k" might be pronounced a bit differently in one environment (for example, after or before another particular sound) from a "k" in another environment, but we can regard them as variants (or allophones) of the same phoneme /k/.

So the phonemes are the distinct sounds of the language.

/ɪ/ and /iː/ are two distinct phonemes. They contrast with one another (e.g. "bit" versus "beat"). This is true of English in general and it's true of General American.

So, they cannot be allophones of the same sound.