To explain patterns we see in language sound systems, we will make reference to two phonetic systems “the talker” articulation, aerodynamics “the listener” acoustics, speech perception
The patterns we see in language sound systems can be classified into two sets: “process” sound alternations, conditioned changes “inventory” set of contrastive sounds in a language
Some examples of this “explanatory phonetics” approach to language sound systems. Process a. Assimilation b. Merger Inventory c. Economy d. Dispersion
a. Assimilation - talker-driven sound change. an old Latin morpheme in English “in-” a newer (OE) morpheme in English “un-” insoluble intolerable inharmonious impossible illogical irrefutable incongruent infrequent unsatisfying untouchable unhappy unpopular unlearnable unreadable unkempt unfamiliar
In assimilation, adjacent or proximal sounds become more similar to each other. In these example two points of contact (e.g. lip, tongue) are replaced by one. How does the older prefix fare compared with the newer one? This can be seen as simplifying the speaker’s task - fewer movements need to be made.
b. Merger - listener-driven sound change. Vowel merger before nasals (in OK and other western states). “pen” [pn] “pin”
Vowels before nasal consonants like [n] tend to be nasalized. Vowel height contrasts (like  versus ) are acoustically reduced in nasalized vowels because the lowest vowel resonance is hidden by nasal resonance and anti-resonance. This purely acoustical consequence of nasal assimilation makes the listener’s task harder. Listeners are then likely to hear  as [ ].
c. Feature Economy- talker-driven inventory constraint. Though redundant perceptual cues might be best for the listener, p b p b t ! t d k k g Unattested stop inventory...