Consonant sounds are described by 3 things:
Typically air is expelled through the mouth (oral cavity). Here is a cross view of a human head, looking to the left.
Source: Department of Linguistics, University of Pennsylvania
The tongue, lips, teeth, and various regions of the mouth constitute places of articulation in the oral cavity. This means that air coming from the lungs is constricted somehow to create consonant sounds.
Here's what consonant sounds look like (the place of articulation) as they are produced in the vocal tract.
Bilabial = two lips. Bilabial consonants are produced by creating a closure with both lips.
Labiodental = lower lip and upper teeth. Labiodental consonants are produced by raising the lower lip to the upper teeth. English has only fricative labiodentals, and no stops.
Interdental = tongue between the teeth, or just behind the upper teeth (also called "dental"). In English, the interdental consonants are also all fricatives. In the ASCII phonetic alphabet, these sounds are the voiced [th] and the voiceless [TH].
Alveolar = tongue tip at the alveolar ridge, behind the top teeth. English alveolar consonants are formed by raising the tip of the tongue to the alveolar ridge, which lies right behind the teeth. There are both fricatives and stops.
Note that languages differ in how related speech sounds are typically produced. For example, the stops 't' and 'd' are alveolar in English, but in languages like Spanish, Italian and French they are typically dental, that is, they are produced with the tongue against the back of the upper teeth (as in todo "all" and detras "in the back of".) This gives 't' and 'd' a different characteristic sound in these languages, and this is also one of the features that we use to identify the non-native accent in a speaker of one of these languages who is learning English.
Palatal = the front or body of the tongue raised to the palatal region or the domed area at the roof of your mouth. In our ASCII phonetic alphabet, these are the voiceless [S] and the voiced [Z]
Velar = the back of the tongue raised to the soft palate ("velum"), the area right behind the palate. As with bilabials, English has a limited range of velar consonants. But these are sometimes pronounced in words borrowed into English from languages which do have velar fricatives, e.g. from German, Bach. The last sound below (looks like a long tail on the letter "n") is the [N] in our ASCII phonetic alphabet.
Glottal = at the larynx (the glottis is the space between the vocal folds). Locate the glottis (the vocal folds) in the diagram, below. A glottal stop is a speech sound articulated by a momentary, complete closing of the glottis in the back of the throat. It exists in many languages, as in English and Hawaiian uh-oh, O'ahu, and ka'aina.
source of graphics: Department of Linguistics, University of Pennsylvania
The airflow can be modified at various points within vocal organs to produce distinct speech sounds. The point where a sound is produced is referred to as its place of articulation.
Ling 102/WI Introduction to the Study of
Language, University of Hawai'i - Leeward Community College
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