ANTERIOR
The feature [anterior] is related to the place or position of articulation of phonemes.
Any phoneme which is articulated at a position closer to the frontal parts of the mouth is [+anterior]; any phoneme articulated at a position closer to the dorsal (or the posterior) parts of the mouth is considered to be [-anterior].
As figure 4.2 shows, all bilabial, labio-dental, dental, alveolar, and palatal sounds are [+anterior]. In contrast, all palato-velar, velar, velo-uvular, uvular, pharyngeal, and glottal sounds are [-anterior].
In English, liquids are [+anterior] while glides (also less technically called semi vowels) are [-anterior].
In addition the phonemes /ʃ/, /Ʒ/, /ʧ/, /ʤ/, and /ŋ/ are [-anterior]. Other English phonemes are [+anterior]. Some phoneticians may use the feature [posterior] instead of the feature [anterior]. In other words, they use [-posterior] instead of [+anterior], and [+posterior] instead of [-anterior].
These rules can be collapsed together to form a single and more general rule. If we use the mathematical symbol α to represent ±, then we can rewrite the above two rules as:
In most cases, however, phoneticians normally prefer not to use the feature [posterior]. The students' attention is drawn to this point so that confusions will not arise if the feature [posterior] is in any writing.
