Stop consonant

In phonetics, a stop, also known as a plosive or oral occlusive, is a consonant in which the vocal tract is blocked so that all airflow ceases.Symbols to the right in a cell are voiced, to the left are voiceless. Shaded areas denote articulations judged impossible.Vowels beside dots are: unrounded • rounded In phonetics, a stop, also known as a plosive or oral occlusive, is a consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be made with the tongue blade (, ) tongue body (, ), lips (, ), or glottis (). Stops contrast with nasals, where the vocal tract is blocked but airflow continues through the nose, as in /m/ and /n/, and with fricatives, where partial occlusion impedes but does not block airflow in the vocal tract. The terms stop, occlusive, and plosive are often used interchangeably. Linguists who distinguish them may not agree on the distinction being made. The terms refer to different features of the consonant. 'Stop' refers to the airflow that is stopped. 'Occlusive' refers to the articulation, which occludes (blocks) the vocal tract. 'Plosive' refers to the release burst (plosion) of the consonant. Some object to the use of 'plosive' for inaudibly released stops, which may then instead be called 'applosives'. Either 'occlusive' or 'stop' may be used as a general term covering the other together with nasals. That is, 'occlusive' may be defined as oral occlusive (stops/plosives) plus nasal occlusives (nasals such as , ), or 'stop' may be defined as oral stops (plosives) plus nasal stops (nasals). Ladefoged and Maddieson (1996) prefer to restrict 'stop' to oral occlusives. They say, In addition, they use 'plosive' for a pulmonic stop; 'stops' in their usage include ejective and implosive consonants. If a term such as 'plosive' is used for oral obstruents, and nasals are not called nasal stops, then a stop may mean the glottal stop; 'plosive' may even mean non-glottal stop. In other cases, however, it may be the word 'plosive' that is restricted to the glottal stop. Note that, generally speaking, stops do not have plosion (a release burst). In English, for example, there are stops with no audible release, such as the /p/ in apt. However, pulmonic stops do have plosion in other environments. In Ancient Greek, the term for stop was ἄφωνον (áphōnon), which means 'unpronounceable', 'voiceless', or 'silent', because stops could not be pronounced without a vowel. This term was calqued into Latin as mūta, and from there borrowed into English as mute. Mute was sometimes used instead for voiceless consonants, whether stops or fricatives, a usage that was later replaced with surd, from Latin surdus 'deaf' or 'silent', a term still occasionally seen in the literature. For more information on the Ancient Greek terms, see Ancient Greek phonology § Terminology. All spoken natural languages in the world have stops, and most have at least the voiceless stops , , and . However, there are exceptions: Colloquial Samoan lacks the coronal , and several North American languages, such as the northern Iroquoian and southern Iroquoian languages (i.e., Cherokee), lack the labial . In fact, the labial is the least stable of the voiceless stops in the languages of the world, as the unconditioned sound change → (→ → Ø) is quite common in unrelated languages, having occurred in the history of Classical Japanese, Classical Arabic, and Proto-Celtic, for instance. Formal Samoan has only one word with velar ; colloquial Samoan conflates /t/ and /k/ to /k/. Ni‘ihau Hawaiian has for /k/ to a greater extent than Standard Hawaiian, but neither distinguish a /k/ from a /t/. 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. See Common occlusives for the distribution of both stops and nasals.