Not Allophones!

My point is, when the same phoneme looks different in different places (has the same IPA representation, but look different on spectrograms) (regarding to speech analysis): (like the following)

  • Tilt
  • Duration
  • Intensity of speaking etc.

What does one call these, are they still the same phoneme, on a finer level of analysis?

  • 1
    Co-articulation doesn't affect duration, like hahaha has three different a's Commented Jan 11, 2019 at 14:14
  • 2
    Can I ask you first how you define/understand "phoneme"?
    – Alex B.
    Commented Jan 11, 2019 at 23:21
  • 3
    @WiccanKarnak but if the same phoneme is "different" how is that not an allophone of the phoneme? Commented Jan 12, 2019 at 10:56
  • 2
    That's still an allophone. The IPA only provides a set of tools to represent sounds, and each symbol corresponds not to one sound but to a class of sounds.
    – Nardog
    Commented Jan 12, 2019 at 13:05
  • 2
    Allophones have different distinctive features, whereas phonetic variations have slight physical differences.
    – amegnunsen
    Commented Jan 12, 2019 at 15:53

3 Answers 3


IMO this is a classical terminological question. In some views, by definition it is an "allophone". The phones are the detailed surface sounds, a symbolic representation of speech without prejudice to what language the sound occurs in. Thus, a very narrow phonetic transcription. Given that [k, kʰ, kʲ, kʲʰ] etc. may all occur in complementary environments and there may be some functional unity to the various k-like sounds, we have the concept of "phoneme" that unifies phones into phonemes (and the relation between phone and phoneme is that of "allophone"). This would in principle include durational facts, amplitude etc. So if you say "not allophones", then you have a different theory of what a phoneme is.

The things that you are talking about are not typically viewed by phoneticians as being categories. There is, in some languages, a categorial distinction in "length" which is significantly correlated with duration. Some practices (Finno-Ugricist especially) extend the typical analysis in terms of "long/short" into multiple categories (under-short, short, over-long etc), where no language exploits all of those length categories contrastively; still, they manage to reduce the durational continuum to more categories. Phoneticians instead would look at the measurable correlates of some categorial distinction, for example the duration of a long vowel in a stressed syllable as contrasted with that of an unstressed syllable. So you could say "we will investigate vowel duration as a function of the length contrast and the stress contrast": but phoneticians don't reify that kind of correlation with a categorial phonological label like "phoneme".

When two things are measurably different but are transcribed the same way, you simply have encountered the limit on how precisely speech can be reduced to symbols. You can expand your list by including different formant transitions patterns being transcribed with the letter [ɪ]. Transcriptional tools for notating spectral tilt, amplitude and duration are pretty limited. The reason for this is that IPA has a strong prejudice in favor of not adding symbols for every phonetic fact – the system explicitly favors contrastiveness as a desideratum for inclusion in the alphabet. Since tilt (per se, as opposed to breathiness as a category) is not contrastive, it isn't included in a transcription (and frankly, you can't hear the computed value H1-H2, you have to measure it).

  • yeah, so I get your point regarding phonology. I get that phoneticians don't look at it from a non-human perspective. So keeping terminology like "allophones" from the field of phonology aside... What I am left with is, does speech processing also not require those finer distinctions? If it does, then what do they call it? Commented Jan 12, 2019 at 20:33

Researchers speak of Segmental Variability or Density of Phonetic Encoding in this respect, see, e.g., Zofia Malisz, Erika Brandt, Bernd Möbius, Yoon Mi Oh, and Bistra Andreeva,Dimensions of Segmental Variability: Interaction of Prosody and Surprisal in Six Languages


I believe phonologists often don't make a distinction between allophonic and non-allophonic variation in the realization of phonemes, but, when they do, it goes something like this: allophonic variation is discrete, driven by a distinction that can be captured as a simple rule, maps to a plausible (and usually independently attested) binary distinction in articulation (and usually in acoustics), and often maps closely to a distinction that is phonetic in other languages (especially ancestral, or at least related, ones).

Consider the difference between the two /k/ sounds in kill and skill:

  • The range in English /k/ sounds looks like two distinct blobs, one centered around a paradigm aspirated /k/, the other around a paradigm unaspirated /k/.
  • If you measure articulatory physiology instead of acoustics, you get much the same results.
  • Many languages—including relatives like Hindi—distinguish /k/ and /kh/ sounds on the basis of a +aspirated feature, and in fact the sound cluster for English /k/ is pretty close to the union of the clusters for Hindi /k/ and /kh/.
  • /k/ may even be the result of a historical merger between separate /k/ and /kh/ phonemes in an ancestral language.
  • The variation can be described by simple rules, like aspirated when it's the first sound in the onset, unaspirated when it's internal to an onset cluster.

Now try the same thing with the /s/ sounds in sill and skill. You get one big amorphous blob, caused by multiple continuously-ranging articulatory differences, none of which match up well with a well-attested phonetic feature used in any language. You can sort of explain why skill is usually less hissy because the tongue moves toward a stop in the middle, but it's hard to make a well-principled phonological rule like "onset = +aspirated".

Of course nothing is ever that perfect. For example, aspiration isn't really binary; you can aspirate harder or softer, and continue aspirating further or less far into the stop, and so on. And the cluster of English /k/ sounds is similar to the union of Hindi /k/ and /kh/, but not identical to it. But I think that's the distinction you're looking for: /k/ in kill vs. skill is the paradigm example for allophones, while /s/ in sill vs. skill is arguably (but it probably depends on a specific definition/theory) not allophonic.

So, what do you call variation like the hissiness of the /s/, or like your examples? There are all kinds of variation that have different names, but I don't think there's a name that covers all of the various kinds that aren't allophonic. I think what you're looking for is something like "(various axes of) non-allophonic variation in phoneme realization", or "non-allophonic (phonetic/segmental) variability", etc.; there is no simpler term.

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