|Places of articulation|
A laminal consonant is a phone produced by obstructing the air passage with the blade of the tongue, which is the flat top front surface just behind the tip of the tongue on the top. This contrasts with apical consonants, which are produced by creating an obstruction with the tongue apex (tongue tip) only. This distinction applies only to coronal consonants, which use the front of the tongue.
Although most languages do not contrast laminal vs. apical sounds, the distinction is found in a number of languages:
- The contrast is very common in Australian languages, where there are usually no fricatives.
- Some languages in South Asia contrast apical and laminal stops. This occurs in Hindustani, for example, where the apical stops are normally called "retroflex" but are properly alveolar or postalveolar. Malayalam has a three-way distinction between laminal dental, apical alveolar and true subapical retroflex in both nasal and voiceless oral stops.
- Basque differentiates between laminal and apical sibilants in the alveolar region, as does Serbo-Croatian, whereas Mandarin and Polish make the distinction with postalveolar consonants.
- Some native languages of California have the distinction in both stops and fricatives.
- Dahalo makes the distinction only in its stops.
Because laminal consonants use the flat of the tongue, they cover a broader area of contact than apical consonants. Laminal consonants in some languages have been recorded with a broad occlusion (closure) covering the entire front of the mouth, from the hard palate to the teeth. Therefore, it is difficult to compare the two: alveolar laminals and apicals are two different articulations.
A very common laminal articulation is sometimes called denti-alveolar; it spans the alveolar ridge to the teeth, but is a little further forward than other alveolar laminal consonants, which cover more of the alveolar ridge (and might be considered postalveolar). This is the situation for French.
Part of the confusion in naming laminal consonants is, quite literally, a matter of point of view: When looking at a person pronouncing a laminal alveolar or denti-alveolar, the tip of the tongue can be seen touching the back of the teeth, or even protruding between the teeth. This gives them the common name of dental. Acoustically however, the important element is where the rear-most occlusion is, for this is the point where the resonant chamber in the mouth terminates, and this determines the size and shape, and therefore the acoustics, of the oral cavity, which produces the harmonics of the vowels. By this consideration the French coronals are alveolar, and differ from English alveolars primarily in being laminal rather than apical (that is, in French the tongue is flatter). There are true laminal dentals in some languages, with no alveolar contact (e.g. in Hindi and Urdu), and they sound different from the French consonants. Nevertheless, the breadth of contact has some importance, for it influences the shape of the tongue further back, and therefore the shape of the resonant cavity. Also, if the release of a denti-alveolar consonant is not abrupt, the tongue may peel off from the roof of the mouth from back to front, in effect shifting from an alveolar to a dental pronunciation.
In the International Phonetic Alphabet, the diacritic for laminal consonants is U+033B ◌̻ COMBINING SQUARE BELOW (HTML