I'm trying to figure out when exactly p, t, k should be aspirated in (American) English.
Here's what I found here:
Voiceless stops are aspirated at the beginning of a word, and at the beginning of a stressed syllable.
Voiceless stops are unaspirated at the beginning of an unstressed syllable. They’re also unaspirated in any other position, like at the end of a syllable or the end of a word.
And even if a syllable is stressed, a voiceless stop is unaspirated if it follows [s].
In English, voiced stops are never aspirated. They’re always unaspirated.
Don't the first two bullet points contradict each other? The first says that voiceless stops are aspirated at the beginning of the word, but the second says that they are unaspirated at the beginning of the word if this syllable is unstressed.
Further, I found this:
Where an English speaker does and doesn't use aspiration is predictable. For most English dialects, the two environments where voiceless plosives are aspirated are:
- At the beginning of a stressed syllable. (The [k] of skill isn't at the beginning of the syllable -- there's a [s] before it.)
- At the beginning of a word -- whether the syllable is stressed or not.
In potato, the p will be aspirated because it is at the beginning of the word and t will be aspirated because it's at the beginning of a stressed syllable: [pʰəˈtʰeɾo].
The second bullet points in this source agrees with the first one of the previous source (but also contradicts "Voiceless stops are unaspirated at the beginning of an unstressed syllable"). So which description is most accurate? If neither of these two is accurate, what's ""the proper" description?