A labial fricative is a fricative consonant, whose articulation involves the lips. Several kinds can be distinguished based on whether the articulation involves only the lips or either the teeth or the tongue:
A fricative is a consonant produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate in the case of German ; or the side of the tongue against the molars, in the case of Welsh. This turbulent airflow is called frication.
Labial consonants are consonants in which one or both lips are the active articulator. The two common labial articulations are bilabials, articulated using both lips, and labiodentals, articulated with the lower lip against the upper teeth, both of which are present in English. A third labial articulation is dentolabials, articulated with the upper lip against the lower teeth, normally only found in pathological speech. Generally precluded are linguolabials, in which the tip of the tongue contacts the posterior side of the upper lip, making them coronals, though sometimes, they behave as labial consonants.
In phonetics, labiodentals are consonants articulated with the lower lip and the upper teeth.
The field of articulatory phonetics is a subfield of phonetics that studies articulation and ways that humans produce speech. Articulatory phoneticians explain how humans produce speech sounds via the interaction of different physiological structures. Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.
The voiced labiodental nasal is a type of consonantal sound. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɱ⟩. The IPA symbol is a lowercase letter m with a leftward hook protruding from the lower right of the letter. Occasionally it is instead transcribed as an with a dental diacritic: ⟨m̪⟩.
The voiceless bilabial fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɸ⟩, a Latinised form of the Greek letter Phi.
In phonetics, a trill is a consonantal sound produced by vibrations between the active articulator and passive articulator. Standard Spanish ⟨rr⟩ as in perro, for example, is an alveolar trill.
Linguolabials or apicolabials are consonants articulated by placing the tongue tip or blade against the upper lip, which is drawn downward to meet the tongue. They represent one extreme of a coronal articulatory continuum which extends from linguolabial to subapical palatal places of articulation. Cross-linguistically, linguolabial consonants are very rare. They are found in a cluster of languages in Vanuatu, in the Kajoko dialect of Bijago in Guinea-Bissau, in Umotína, and as paralinguistic sounds elsewhere. They are also relatively common in disordered speech, and the diacritic is specifically provided for in the extensions to the IPA.
The sj-sound is a voiceless fricative phoneme found in the sound system of most dialects of Swedish. It has a variety of realisations, whose precise phonetic characterisation is a matter of debate, but which usually feature distinct labialization. The sound is represented in Swedish orthography by a number of spellings, including the digraph ⟨sj⟩ from which the common Swedish name for the sound is derived, as well as ⟨stj⟩, ⟨skj⟩, and ⟨sk⟩. The sound should not be confused with the Swedish tj-sound, often spelled ⟨tj⟩, ⟨kj⟩, or ⟨k⟩.
The voiceless labiodental affricate is a rare affricate consonant that is initiated as a labiodental stop and released as a voiceless labiodental fricative.
In phonetics, the voiced labiodental flap is a speech sound found primarily in languages of Central Africa, such as Kera and Mangbetu. It has also been reported in the Austronesian language Sika. It is one of the few non-rhotic flaps. The sound begins with the lower lip placed behind the upper teeth. The lower lip is then flipped outward, striking the upper teeth in passing.
Bidental consonants are consonants articulated with both the lower and upper teeth. They are normally found only in speech pathology, and are distinct from interdental consonants such as, which involve the tongue articulated between the teeth rather than the teeth themselves. The diacritic for bidental consonants in the extensions to the IPA is the same superscript plus subscript bridge, ⟨◌̪͆⟩. This is used for sounds most commonly found in disordered speech:
The voiced labiodental plosive or stop is a consonant sound produced like a, but with the lower lip contacting the upper teeth, as in. This can be represented in the IPA as ⟨b̪⟩. A separate symbol that is sometimes seen, especially in Bantu linguistics, but not recognized by the IPA, is the db ligature⟨ȸ⟩.
The voiceless linguolabial fricative is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents it is ⟨θ̼⟩ or ⟨ɸ̺⟩.
The voiced linguolabial fricative is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents it is ⟨ð̼⟩ or ⟨β̺⟩.
The voiced labiodental affricate is a rare affricate consonant that is initiated as a voiced labiodental stop and released as a voiced labiodental fricative.
The voiceless bilabial affricate is a rare affricate consonant that is initiated as a bilabial stop and released as a voiceless bilabial fricative. It has not been reported to occur phonemically in any language.
The bilabial ejective fricative is a rare type of consonantal sound. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɸʼ⟩.