d. Aspiration
Voiced stops (in English) are never aspirated.
Voiceless stops are sometimes aspirated and sometimes not.
These voiceless stops will be aspirated:
a. Word-initial, regardless of stress:
tap, cat, Topeka (stop precedes an unstressed vowel), command (ditto)
[thQp] [khQt] [th
kh
]
b. Intervocalic (between 2 vowels) but only when
preceding a stressed vowel.
meticulous, repair, recalcitrant, return
These voiceless stops will be unaspirated:
a. Following /s/
stop, skate, stick, stare, spike
b. Intervocalic, preceding an unstressed vowel
napping, camper, sicken, supper, thirsty
(Note: Sometimes these are unaspirated,
sometimes they are lightly aspirated.)
See Table 5-2 (p. 96) of MacKay for a nice summary
with examples.
Voice Onset Time (VOT)
[phA]
VOT ~85 ms
[bA]
VOT ~0 ms
voicing onset
release
voicing onset and
release ~ simultaneous
VOT = Interval between articulatory release
and onset of voicing.
Voice Onset Time (VOT)
[phAt]
[spAt]
VOT ~10 ms
VOT ~85 ms
voicing onset
release
Very short delay
between release and
voicing onset (~10 ms)
[spAt] (unaspirated [p])
With [s] edited out
pack [phQk]
(aspirated [p])
/p/ precedes
stressed vowel
(aspirated)
capping [khQpIN]
(lightly aspirated [p])
/p/ precedes
unstressed vowel
(unaspirated or
lightly aspirated)