I am having some trouble distinguishing ''aspiration'' from ''voice'' for plosives.

Now I know ''aspiration'' and ''voice'' sound like completely different concepts but let's take /p/ for example. /p(h)/ as in ''pot'' is an aspirated voiceless plosive, right. And /p/ in ''spot'' is an unaspirated allophone of /p/ which to my ear sounds exactly like its VOICED counterpart /b/.

So is it the case that for voiceless plosives, unaspirating them is the same as voicing them; for voiced plosives, aspirating them is the same as devoicing them, e.g., the ending of ''periodt.'' Ok maybe the case for voiced plosives is kind of a stretch. But would the equivanlence between voicing and unaspiration stand for the voiceless stops?

  • "And /p/ in ''spot'' ... to my ear sounds exactly like its VOICED counterpart /b/". Wow, what is your mother tongue? To my ear they sound so much different that I am completely missing the point of your question. Commented Aug 23, 2022 at 14:34

3 Answers 3


For many languages, distinctions in aspiration and voicing mostly come down to a single parameter: the "voice onset time". In other words, do the vocal chords start vibrating before the closure is released (voiced), after it's released (aspirated), or around the same time (tenuis = unvoiced unaspirated)?

Since this is a measure of time, you can have a "really voiced" stop (very negative VOT), a "kind of voiced" stop (slightly negative VOT), a "kind of aspirated" stop (slightly positive VOT), a "really aspirated" stop (very positive VOT), or anywhere in between. And different languages can, and do, draw their boundary lines in different places!

In English, for example, the boundary between our two types of stops is more on the aspirated side. Our fortis (higher VOT) stops tend to be very aspirated, and our lenis (lower VOT) stops tend to be not very voiced (or sometimes not voiced at all). Spanish also has two categories of stops, but their boundary is more on the voiced side; their fortis stops are not very (or not at all) aspirated, and their lenis stops are very voiced.

From the way your question is phrased, I'm guessing you speak a language that puts the boundary more on the aspirated side. Unaspirating a stop might not actually make it truly "voiced"—the VOT might not actually go negative—but the VOT will become less positive, which might push it over that mental dividing line you developed while learning your native language. That makes it fall into the lenis ("voiced") category in your mind.


It depends on what language you are talking about, what language you speak, and whether you are talking about phonological analysis, or physical implementation.

Terminologically speaking, we usually talk about classes of sounds with categorical phonological terms, such as "voiced", "(un)aspirated", "ejective", "implosive" and so on. However, the way that sounds of a particular category are not physically produced in just one way, there is a range of known pronunciations. Another way to talk about language sounds is in terms of measurable physical properties, such as "vocal fold vibration" or "voice onset time" – ultimately you are looking for a number. In the case of voicing and aspiration, there has been a quest (for over a half century) to understand the relationship between phonological categories like "voiced" and "aspirate" and their physical phonetic realization.

Assuming that you are a native speaker of English, and with reference to your feeling about the p in "pot" and the b in "bought", there is an experiment that could be performed on you to test these feelings. The underlying issue is that you almost certainly can hear that the p in "spot" is distinct as a physical sound from the b in "bought", but in terms of finding the closest auditory analog, unaspirated [p] (created by editing initial /sp/ clusters) is not identical to initial /b/, but it is closer to initial /b/ than it is to initial /p/ (which is realized as [pʰ]). In other words, if you ask a question that probes auditory perception, you get one result, but if you as a question that probes the connection between perception and phonological analysis, you get a different result. In English (US English, I don't know about UK speakers).

There is a debate for English whether one should treat /p/ as /pʰ/ and /b/ as /p/, as opposed to the conventional /p,b/ analysis. One way that people have attempted to resolve the discussion is by appeal to other languages – /b/ of English is physically distinct from /b/ of French. This is somewhat appropriate since people usually think that the classificatory labels refer to physical properties. However, it is also the case that /b/ in English is not physically realized identically in all contexts including dialects: in general, language sounds don't have just one physical realization. English isn't the only language like this – North Saami stops are phonetically rather similar to English stops (but not in Finland dialects).

Advocates of the /p,pʰ/ hypothesis don't deny that their /p/ is sometimes voiced (produced with vocal fold vibration), they just attribute that to a separate rule of phonetic implementation. This is the converse of the position held by advocates of the /b,p/ hypothesis that sometimes /b/ is realized as [p] but remember that in those contexts, /p/ is realized as [pʰ] hence they are still distinct. In pre-pausal position, there is physical devoicing hence "height" and "hide" are phonetically different and there isn't aspiration. If you inspect spectrograms, you will see that /d/ in "hide" is partially-devoiced, at the right edge of the stop, whereas there is no voicing in "height" (instead, there is early glottal closure).

This is the sense in which voicing and aspiration are "the same" – it depends on the kind of analysis you are performing. I think the confusion largely arises from assuming that phonological analysis is the same as phonetic analysis.


No, it is not the case that aspirating them is the same as devoicing them.

It happens to be the case in English that in most contexts unvoiced plosives are aspirated, so we are not used to hearing unaspirated plosives, But in many languages (for example, most languages of India) aspiration and voice are independent, and in some languages all four combinations exist and are distinct.

  • 2
    Aspiration of voiced plosives is not really aspiration in the normal sense of the word, apparently. Commented Aug 22, 2022 at 20:50
  • Thank you! I did not realize English wasn't really a great reference language for studying the distinctions between voicing and aspiration and different combinations of them as they are lacking in English.
    – Jenny
    Commented Sep 7, 2022 at 7:00

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