A stop, plosive, or occlusive is
sound produced by stopping the airflow in the vocal
tract. The terms plosive and stop are
usually used interchangeably, but they are not perfect
synonyms. Plosives are oral
stops with a pulmonic
mechanism. The term is also used to describe oral
(non-nasal) stops. Many use the term nasal continuant
rather than nasal stop to refer to sounds like
[n] and [m]. One should be aware that this article treats
these "nasal continuants" as nasal stops.
All languages in the world have stops
and most have at least [p], [t], [k], [n], and [m]. However,
there are exceptions: Colloquial Samoan
lacks the coronals
[t] and [n], and the several North American languages,
such as the northern Iroquoian
languages, lack the labials
[p] and [m]. Some of the Chimakuan,
languages near Puget
Sound lack nasal
stops [m] and [n], as does the Rotokas
language of Papua
New Guinea, and Eyak
lacks both labials and nasals, [p], [m], [n].
In some African and South American languages, nasal stops
occur, but only in the environment of nasal
vowels, and so are not distinctive. Formal Samoan
has only one word with velar
[k], but it has a nasal velar stop, [ŋ]. Ni‘ihau
which has /t/ for Standard Hawaiian /k/, can be analysed
as having no velars, but in fact its /t/ and /n/ vary
in pronunciation, [t]~[k] and [n]~[ŋ]. It may be
more accurate to say that Hawaiian and colloquial Samoan
do not distinguish velar and coronal stops than to say
they lack one or the other.
In the articulation of the stop, three phases can be
- Catch: The airway closes so that no air can
escape through the mouth (hence the name stop).
With nasal stops, the air escapes through the nose.
- Hold or occlusion: The airway stays
closed, causing a pressure difference to build up (hence
the name occlusive).
- Release or burst: The closure is opened.
In the case of plosives, the released airflow produces
a sudden impulse causing an audible sound (hence the
In many languages, such as Malay
final stops lack a release burst, or have a nasal
release. See Unreleased
stops, the release is a fricative.
Classification of stops
stops are articulated with simultaneous vibration
of the vocal
stops without. Plosives are commonly voiceless, whereas
nasal stops are only rarely so.
stops, the voice onset (the time when the vocal
cords begin to vibrate) comes perceivably later than
the release of the stop. The duration between the release
of the stop and the voice onset is called voice
onset time (VOT). Tenuis
stops have a voice onset time close to zero, meaning that
voicing begins when the stop is released. Voiced stops
have a negative voice onset time, meaning the voicing
begins before the stop is released. A stop is called "fully
voiced" if it is voiced during the entire occlusion. In
English, however, initial voiced plosives like [b] or
[d] are only partially voiced, meaning that voicing picks
up sometime during the occlusion. Aspirated stops have
a voice onset time greater than zero, so that there is
a period of voiceless airflow (a phonetic [h])
before the onset of the vowel.
In most dialects of English, the final g in the
word bag is likely to be fully voiced, while the
initial b will be only partially voiced. Initial
voiceless plosives, like the p in pie, are
aspirated, with a palpable puff of air upon release, while
a plosive after an s, as in spy, is tenuous.
When spoken near a candle flame, the flame will flicker
more after the words par, tar, and car
are articulated, compared with spar, star,
In a geminate
or long stop, the occlusion lasts longer than in
normal stops. In languages where stops are only distinguished
by length (e.g. Arabic, Ilwana, Icelandic), the long stops
may last up to three times as long as the short stops.
is well known for its geminate stop, as the double t
in the name Vittoria takes just as long to say
as the ct does in English Victoria. Japanese
also prominently features the geminate consonant, such
as in the minimal pair 来た (kita), meaning
came, and 切った (kitta) meaning
Note that there are many languages where the features
voice, aspiration, and length reinforce each other, and
in such cases it may be hard to tell which of these features
predominates. In such cases the terms fortis
is sometimes used for aspiration or gemination, while
is used for single, tenuous or voiced stops. Beware, however,
that the terms fortis and lenis are poorly
defined, and their meanings vary from source to source.
stops are differentiated from oral stops only by a
that allows the air to escape through the nose during
Nasal stops are acoustically sonorants,
as they have a non-turbulent airflow and are nearly always
voiced, but they are articulatorily obstruents,
as there is complete blockage of the oral cavity.
stop starts out with a lowered velum that raises during
the occlusion. The closest examples in English are consonant
clusters such as the [nd] in candy, but many languages
have prenasalized stops that function phonologically as
single consonants. Swahili
is well known for having words whose spellings begin with
mp or nd, like mtu, though truer
prenasalized sounds like [mp] or [nd] do occur word-initially
in other Bantu languages.
stop begins with a raised velum that lowers during
the occlusion. This causes an audible nasal release,
as in English sudden. Russian
and other Slavic languages have words that begin with
[dn], which can be seen in the name of the Dnieper
Note that the terms prenasalization and postnasalization
are normally only used in languages where these sounds
are phonemic, that is, not analyzed into sequences of
plosive plus nasal stop.
Stops may be made with more than one airstream
mechanism. The normal mechanism is pulmonic
egressive, that is, with air flowing outward from
the lungs. All languages have pulmonic stops. Some languages
have stops made with other mechanisms as well: ejective
ingressive), or click
stop (in the narrow sense) is produced with more muscular
tension than a lenis
stop (in the narrow sense). However, this is difficult
to measure, and there is usually debate over the actual
mechanism of alleged fortis or lenis consonants.
There are a series of stops in Korean,
sometimes written with the IPA symbol for ejectives, which
are produced using "stiff
voice", meaning there is increased contraction of
the glottis than for normal production of voiceless stops.
The indirect evidence for stiff voice is in the following
vowels, which have a higher fundamental frequency than
those following other stops. The higher frequency is explained
as a result of the glottis being tense. Other such phonation
types include breathy
voice, or murmur; slack
voice; and creaky
Here are the oral stops (plosives) granted dedicated
symbols in the IPA.
See also the nasal
(aspirated word-initially, tenuis in clusters with s)
(in most dialects: partially voiced word-initially, fully
(glottal stop, not as a phoneme
in most dialects)
König, W. (ed) dtv Atlas zur deutschen Sprache
Michael Krauss, 1965. "Eyak: a preliminary report".
In Canadian Journal of Linguistics. Note that
the /m/ reported in the Wikipedia article on Eyak is
not a normal speech sound.