Alveolar ridge in the context of "Alveolar consonant"

Voiceless alveolar fricatives are a type of fricative consonant pronounced with the tip or blade of the tongue against the alveolar ridge (gum line) just behind the teeth. This refers to a class of sounds, not a single sound. There are at least six types with significant perceptual differences:

• A voiceless alveolar sibilant [s] (the standard symbol in the International Phonetic Alphabet or IPA) has a strong hissing sound, as the s in English sink. It is one of the most common sounds in the world.
• A voiceless denti-alveolar sibilant [s̄] (an ad hoc notation), also called apico-dental, has a weaker lisping sound like English th in thin. It occurs in Spanish dialects in southern Spain (eastern Andalusia).
• A voiceless alveolar retracted sibilant [s̠], and the subform apico-alveolar [s̺], or called grave, has a weak hushing sound reminiscent of retroflex fricatives. It is used in the languages of northern Iberia, like Asturleonese, Basque, Peninsular Spanish (excluding parts of Andalusia), Catalan, Galician, and Northern European Portuguese. A similar retracted sibilant form is also used in Dutch, Icelandic, some southern dialects of Swedish, Finnish, and Greek. The retracted "S" is also used in Amerindian languages such as Muscogee, Garifuna, and many varieties of Quechua. It was supposedly the standard sound of s in Classical Latin. Its sound is between [s] and [ʃ].
• A voiceless alveolar non-sibilant fricative [θ̠] or [θ͇], using the alveolar diacritic from the Extended IPA, is similar to the th in English thin. It occurs in Icelandic as well as an intervocalic and word-final allophone of English /t/ in dialects such as Hiberno-English and Scouse.
• A voiceless alveolar lateral fricative [ɬ] sounds like a voiceless, strongly articulated version of English l (somewhat like what the English cluster **hl would sound like) and is written as ll in Welsh.

The first three types are sibilants, meaning that they are made by directing a stream of air with the tongue towards the teeth and have a piercing, perceptually prominent sound.

A voiceless alveolar affricate is a type of affricate consonant pronounced with the tip or blade of the tongue against the alveolar ridge (gum line) just behind the teeth. There are several types with significant perceptual differences:

• The voiceless alveolar sibilant affricate [t͡s] is the most common type, similar to the ts in English cats.
• The voiceless alveolar non-sibilant affricate [t͡θ̠] or [t͡θ͇], using the alveolar diacritic from the Extended IPA, is somewhat similar to the th in some pronunciations of English eighth. It is found as a regional realization of the sequence /tr/ in some Sicilian dialects of Standard Italian.
• The voiceless alveolar lateral affricate [t͡ɬ] is found in certain languages, such as Cherokee, Mexican Spanish, and Nahuatl.
• The voiceless alveolar retracted sibilant affricate [t͡s̺], also called apico-alveolar or grave, has a weak hushing sound reminiscent of retroflex affricates. One language in which it is found is Basque, where it contrasts with a more conventional non-retracted laminal alveolar affricate.

A retroflex (/ˈrɛtrəflɛks, -roʊ-/ ) or cacuminal (/kəˈkjuːmɪnəl/ ) consonant is a coronal consonant where the tongue has a flat, concave, or even curled shape, and is articulated between the alveolar ridge and the hard palate. They are sometimes referred to as cerebral consonants—especially in Indology.

The Latin-derived word retroflex means "bent back"; some retroflex consonants are pronounced with the tongue fully curled back so that articulation involves the underside of the tongue tip (subapical). These sounds are sometimes described as "true" retroflex consonants. However, retroflexes are commonly taken to include other consonants having a similar place of articulation without such extreme curling of the tongue; these may be articulated with the tongue tip (apical) or the tongue blade (laminal). When apical, they have been called apico-domal consonants.

A voiced alveolar affricate is a type of affricate consonant pronounced with the tip or blade of the tongue against the alveolar ridge (gum line) just behind the teeth. There are several types with significant perceptual differences:

• The voiced alveolar sibilant affricate [d͡z] is the most common type, similar to the ds in English lads.
• The voiced alveolar non-sibilant affricate [dð̠], or [dð͇] using the alveolar diacritic from the Extended IPA, is found, for example, in some dialects of English and Italian.
• The voiced alveolar retracted sibilant affricate [d͡z̺]

Postalveolar (post-alveolar) consonants are consonants articulated with the tongue near or touching the back of the alveolar ridge. Articulation is farther back in the mouth than the alveolar consonants, which are at the ridge itself, but not as far back as the hard palate, the place of articulation for palatal consonants. Examples of postalveolar consonants are the English palato-alveolar consonants [ʃ] [tʃ] [ʒ] [dʒ], as in the words "ship", "'chill", "vision", and "jump", respectively.

There are many types of postalveolar sounds—especially among the sibilants. The three primary types are palato-alveolar (such as [ʃ ʒ], weakly palatalized; also alveopalatal), alveolo-palatal (such as [ɕ ʑ], strongly palatalized), and retroflex (such as [ʂ ʐ], unpalatalized). The palato-alveolar and alveolo-palatal subtypes are commonly counted as "palatals" in phonology since they rarely contrast with true palatal consonants.