On paper, the words "speak" and "peak" should be pronounced the same (other than the "s") so why does the "p" in "peak" sound so much more explosive?

/spiːk/ vs /piːk/

  • The only difference is the s. And I don't think it is "more explosive". spike and pike.
    – Lambie
    Commented Apr 28 at 18:26

2 Answers 2


I suspect that most native speakers, on reading you question, spent a few minutes saying "peak" and "speak" a few times. Because if there is a difference, it isn't necessarily a conscious one. I agree that there often is a difference as you describe, but not always.

The difference in the way the "p" in "speak" and "peak" can sound in some pronunciations is due to a linguistic concept called aspiration. In English, many consonant sounds can be aspirated or unaspirated, meaning there's a puff of air accompanying the sound.

In "peak", the "p" is more likely to be aspirated (because it is the initial sound), meaning there's a strong burst of air when it is pronounced, although not everyone will pronounce it as strongly. This aspiration adds emphasis and makes the "p" sound more explosive. However, in "speak", the "p" is normally unaspirated because it is following another letter. It doesn't have that strong burst of air because you've already expelled some air pronouncing the "s". This lack of aspiration makes it sound softer and less explosive. So, even though the "p" in both words is technically the same sound, the presence or absence of aspiration changes the way we perceive it.

Other factors can affect how words are pronounced - for example, if the word "peak" was preceded by an "s" sound - for example "widow's peak", then the "p" is likely to be softened as in "speak".

  • 1
    Native English speakers think of them as the same sound and don't notice the difference because it doesn't help distinguish English words—[spʰi:k] (with aspiration) would not be a different word, it would just sound funny!
    – nschneid
    Commented May 1 at 19:58
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    @nschneid True, but not true without the s—AmE and BrE native speakers routinely run into confusion with Indian English speakers who never aspirate, hearing /p/ as /b/ and similar. They might not have the words to explain what happened though. Commented May 1 at 20:18
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    I would give the opposite summary: even though the "p"s in each word are technically different sounds, the presence or absence of aspiration nonetheless doesn't change the way we (native speakers) perceive them.
    – mudri
    Commented May 3 at 7:25
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    Technically, they are not the same sound. Although most English speakers don’t hear the difference because it never carries meaning in English, they are different. In Mandarin, for instance, aspiration is contrastive. The only difference between the pronunciations of 肚子饱了 (belly is full) and 兔子跑了 (The rabbit ran away) is that the former has a pair of unaspirated sounds (in 肚 and 饱), while the latter has their aspirated counterparts (in 兔 and 跑). Commented May 11 at 16:41
  • Thank you this is a great answer! The comments also add great details. Commented May 14 at 17:07

Because the phoneme /p/ is realised in phonetically different ways in different contexts - specifically, as Astralbee says, in most varieties of English, it is aspirated [pʰ] when syllable-initial, but not when it follows /s/ in the same syllable.

Another example is that the /k/ sound in "call" and "kill" is usually subtly different: in "kill", part of the tongue lies along the palate, while in "call" it does not. (The different spelling is not relevant). If you used the sound "kill" for the word "call" it would sound a bit strange, but hearers would probably not be able to work out why. In some cases, they might hear it as "kyall".

Generally speakers of a language will hear all variants of a phoneme as "the same sound" and will not notice any difference unless their attention is drawn to it; but another language may regard these two variants as different sounds, i.e. they are different phonemes in the other language.

  • Thank you, this is a great answer! Commented May 14 at 17:08

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