{{See also, grave and acute (phonetics)
From an articulatory perspective, phonemes can be described as front or back.
Front vowel
A front vowel is a class of vowel sounds used in some spoken languages, its defining characteristic being that the highest point of the tongue is positioned as far forward as possible in the mouth without creating a constriction that would otherw ...
s refer to vowels articulated towards the front of the mouth. This can either refer to vowels that are more front than
central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
or, more rarely, only to fully front vowels, i.e. the ones that are articulated as far forward as possible in the mouth. A similar distinction holds for
back vowel
A back vowel is any in a class of vowel sound used in spoken languages. The defining characteristic of a back vowel is that the highest point of the tongue is positioned relatively back in the mouth without creating a constriction that would be c ...
s, which can refer to vowels that are more back than central or, more rarely, only to fully back vowels, i.e. the ones that are articulated as back as possible in the mouth. However, acoustically there is little difference between a
central vowel
A central vowel, formerly also known as a mixed vowel, is any in a class of vowel sound used in some spoken languages. The defining characteristic of a central vowel is that the tongue is positioned halfway between a front vowel and a back v ...
and a
back vowel
A back vowel is any in a class of vowel sound used in spoken languages. The defining characteristic of a back vowel is that the highest point of the tongue is positioned relatively back in the mouth without creating a constriction that would be c ...
, with the result that the two are frequently grouped together into an even broader category of "back vowels", or a category of "non-front vowels".
A back consonant includes all consonants whose place of articulation is in the soft palate (velum) or farther back, including velar, uvular, pharyngeal, and
glottal consonant
Glottal consonants are consonants using the glottis as their primary articulation. Many phoneticians consider them, or at least the glottal fricative, to be transitional states of the glottis without a point of articulation as other consonants ...
s. From the perspective of primary places of articulation, this includes all of the laryngeal consonants and some of the dorsal consonants (specifically, excluding palatal consonants).
A front consonant includes all consonants that are not back consonants, including palatal, coronal, and labial consonants.
Front and back vowels are also known as acute and grave vowels, respectively.
For consonants, however, front/back are not synonyms of acute/grave. Grave consonants include both back consonants and labial consonants, while acute consonants include all of front consonants ''except'' labial consonants. This suggests that a three-way division between labial, acute and back (vaguely speaking, "P-like", "T-like" and "K-like", respectively) might be useful in some contexts.