What is a ‘social meaning’? What perceptions are controlled by ‘preferring’ one? Where in your model do preferences for social meanings appear?
I stand corrected. It does involve gradual averaging of Labov’s ‘centralization index’ abstraction (CI).
CI is a convenient abbreviation for a narrow range of variation in two perceptual variables, the center frequencies in the lowest two bands of amplified harmonics in the speech sound, called the the first formant and second formant. ‘Centralization index’ is not a common term of art in the field. Labov appears to have invented it for the sake of a compact representation in his tables.
These variables, F1 and F2, are co-varied over much wider ranges to produce and perceive the full range of vowel and consonant sounds. It is possible but very unlikely that speakers in this population developed a unique CI perceptual input function, and combining them into one higher-level ‘amount of centralization’ variable is not necessary to account for control of sounding like or unlike others. As a confound, greater or lesser centralization of all vowels is a function of gain (careful pronunciation vs. lax, unstressed pronunciation).
What is involved here is a change in the articulatory/acoustic reference values for the onset of the two diphthongs. Reference values may be achieved in careful, high-gain pronunciation, but typically are not completely attained, and control is typically disturbed by control of what comes immediately before and after (‘co-articulation effects’). Individuals displaying social identification with high gain control the socially differentiated reference value with high gain. The observed phenomenon of hypercorrection resulted.
But set that aside.
The model asserts that individuals approximate to one another’s pronunciation at each encounter. It is an obvious truism in linguistics that people often do this, but together with the contrary observation that individuals may differentiate features of their own pronunciation from values of those features as perceived in others, or they may exaggerate the observed values or extend them beyond the range in which they can be observed in others. Labov provides data on both of these phenomena, and both are important for the questions that he was investigating and for the explanation that he discovered. Those questions were, why did an extended period of gradual approximation come to an end and then reverse the direction of change, and why was the reversal generalized from the environment before a high back vowel (as in bout) to the environment before a high front vowel (as in bite). The investigation disclosed that the generalization took place in a subpopulation, adolescents, but only in that further subpopulation who intended not to move away. It is clear that this was due to their controlling higher level variables, and Labov clearly said so, although he did not use control theoretic terms.
If the individual’s pronunciation changes during or due to an encounter, it is because a higher level of control changes the reference values for the variables involved.
There is no such fragility in the data, including data from many other such investigations in New York and Philadelphia, and elsewhere by others. This defect in the model might be remedied by modeling higher levels of control adjusting reference values for formants, rather than making those changes an uncontrolled consequence of proximity or ‘encounter’.
The collective value for a group ‘suddenly diverging to a new value’ in real population speech data would be due higher-level systems correcting error in their input by changing references for these perceptions at lower levels. Such higher-level perceptions are amply represented in Labov’s paper.
Much of the language difference depended upon whaling terms which are now obsolete. It is not unnatural, then, to find phonetic differences becoming stronger and stronger as the group fights to maintain its identity.
What is it for a group to have an identity, and for members of it to control perception of that identity with high gain? (I hope you have no objection to that PCT translation of “the group fights to maintain its identity.”)
This gradual transition to dependency on, and outright ownership by the summer people has produced reactions varying from a fiercely defensive contempt for outsiders to enthusiastic plans for furthering the tourist economy. A study of the data shows that high centralization of /ai/ and /au/ is closely correlated with expressions of strong resistance to the incursions of the summer people.
Does this support a model of imitating those who you most frequently encounter?