Why is /h/ called voiceless vowel phonetically, and /h/ consonant phonologically?

  • Good question, but also a basic one (as jlwaler pointed out), and I'm sure you could have found lots of information by googling this (-1).
    – robert
    Commented Nov 4, 2013 at 17:08

2 Answers 2


A good question, and a very basic one that illustrates an important difference between Phonetics and Phonology (or, as it used to be called, Phonemics): They use different criteria for what's a vowel and what's a consonant.

First, an important caveat:

  • This is only true of English; i.e, it's the English phoneme /h/ we're talking about.
    (This is not, for example, true of the Malay phoneme /h/.)
    Phonemes and Phonology are localized to individual languages,
    whereas Phonetics is independent of individual language systems.

What that means is that when an English speaker pronounces the words

  • heat, hit, hate, hen, hat, hot,
    for instance,

they are pronouncing the phoneme strings

  • /hit/, /hɪt/, /het/, /hɛn/, /hæt/, /hat/

Phonemically, and using /h/ as a Phonological consonant.

Phonological consonants are sounds that pattern in some language

  1. on the borders of syllables,
  2. and that are not used in those languages as syllable nuclei, like voiced vowels are in English.

The key word here is Pattern.
Phonology is all about the patterns that sounds fit into in a given language.
In English, /h/ patterns as a consonant, and that's that.

However, in pronouncing those phoneme strings
-- which represent the way speakers hear the words --
the actual /h/ sounds that the speaker says can be classified physiologically as voiceless vowels,
because a Phonetic vowel is defined by how it's pronounced,
rather than how it patterns with other sounds.

Phonetic vowels are produced by passing lung air through the open mouth
and without significant contact between any articulators.
I.e, vowels are differentiated only by the positions of the tongue and the lips.

For historical reasons, English /h/ only occurs before vowels.
It never occurs before a consonant, or at the end of a word (i.e, before Zero).
It used to occur everywhere, but those /h/'s went silent or mutated,
and are represented in English spelling as GH.
Which is why words with GH in them are so perplexing.

Now, the biggest difference between an /h/ and a following vowel is that
the vowel is voiced, whereas the /h/ is voiceless.

Further, there is not much friction necessary to distinguish an /h/ from its absence, which is the only thing it contrasts with, so all that is really needed is a transition
between voiceless and voiced occurring after the vowel has started.
Rather like the Greek concept of a "rough breathing" (Greek only had /h/ before vowels, too).

And the easiest way to accomplish this reliably and efficiently turned out to be
to pronounce /h/ with a different allophone for every vowel it preceded, like

  • [i̥it], [ɪ̥ɪt], [e̥et], [ɛ̥ɛn], [æ̥æt], [ḁat]

A vowel symbol with a circle below represents a voiceless (whispered) vowel.
Any English speaker can prove this to themself easily:

  • whisper eat, it, ate, ett, at, ott, holding the vowel long, to hear its voiceless sound
    then whisper each vowel, but start voicing the vowel and continue with the word.
    You'll hear an /h/ in each case, if you're an Engish native speaker.
    And, if you're paying attention, you'll notice you don't move your tongue -- only your larynx
    which means you're saying a different voiceless vowel in each case.

English has no other uses for voiceless vowels,
so they're available as allophones for /h/.
Language rarely wastes resources.

  • 6
    +1. It might be worth noting that, in continuous speech, /h/ is actually very often phonetically voiced in certain environments (e.g. between vowels). The amplitude of the voicing usually decreases, but it rarely turns off all the way (they usually gloss over this fact in Intro to Linguistics because it complicates the picture). It can still be distinguished from a vowel because of the increased level of aspiration noise that co-occurs with the voicing. Synthesized speech produced with all /h/s completely devoiced sounds supremely unnatural, as if the speaker has laryngitis or something! Commented Nov 4, 2013 at 22:19
  • 1
    What is the Malay phoneme /h/ then?
    – junius
    Commented Jan 20, 2017 at 13:32
  • 3
    The Malay phoneme has its own set of allophones, which include IPA [h] in final position -- i.e, when you say rumah. the Malay word for 'house', you actually have to pronounce the final H. Otherwise the word is ruma, which is wrong. It's also pronounced before consonants, like Rahman. English speakers are used to treating a lot of H's as silent, but they're not silent in Malay.
    – jlawler
    Commented Jan 20, 2017 at 14:40
  • 1
    In English? No, <gh> isn't the phoneme /x/ -- English never had one. <gh> usually represents [x], a former allophone of English /h/, which now has only prevocalic allophones. When the [x] disappeared from people's speech (which took several generations), it got smeared over other fricatives (they're hard to distinguish as you grow old), so that now there are,for instance, words with <gh> that are pronounced as /f/, like laugh.
    – jlawler
    Commented Jul 29, 2018 at 20:34
  • 2
    @melboiko To be fair, calling the phoneme /x/ would be just as valid as calling it /h/ (since it was realized as both). But yeah, as jlawler says, all the [x]s disappeared, in different ways in different dialects (which is why the pronunciation of <gh> is so unpredictable: originally it was totally regular within each dialect, but then they all mixed together and some were considered standard and others weren't, and we ended up with trough and through and bough and all that mess.
    – Draconis
    Commented Mar 31, 2019 at 22:52

English h is not a voiceless vowel; it's a voiceless glide -- the non-syllabic counterpart to a voiceless vowel. (If it were syllabic, it would be a voiceless vowel.)

I disagree with Lawler's answer above only in regard to his omission of a non-syllabic mark on the first sound of [i̥it], [ɪ̥ɪt], [e̥et], [ɛ̥ɛn], [æ̥æt], [ḁat], which he writes as though each word had two syllables.

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