Variationist treatments of phonological processes typically provide precise quantitative accounts of the effects of conditioning environmental factors on the occurrence of the process, and these effects have been shown to be robust for several well-studied processes. But comparable precision in theoretical explanation is usually elusive, at the current state of the discipline. That is, the analyst is usually unable to say why the parameters should have the particular values that they do, although one can often explain relative ordering of environments. This article attempts to give a precise explanation — in the form of a quantitative theoretical prediction — of one robust quantitative observation about English phonology. The reduction of final consonant clusters (often called -t,d deletion) is well-known to be conditioned by the morphological structure of a target word. Deletion applies more in monomorphemic words (e.g., mist) than in inflected words (e.g., missed). In the theory of lexical phonology, these classes of words are differentiated by derivational history, acquiring their final clusters at different levels of the morphology. The theory further postulates that rules may apply at more than one level of the derivation. If -t,d deletion is treated as a variable rule with a fixed rate of application (p0) in a phonology with this architecture, then higher rates of application in underived forms (where the final cluster is present underlyingly and throughout the derivation) are a consequence of multiple exposures to the deletion rule, whereas inflected forms (which only meet the structural description of the rule late in the derivation) have fewer exposures and lower cumulative deletion. This further allows a precise quantitative prediction concerning surface deletion rates in the different morphological categories. They should be related as an exponential function of p0, depending on the number of exposures to the rule. The prediction is empirically verified in a study of -t,d deletion in seven English speakers.

Subject/verb agreement and subject/predicate adjective agreement in spoken Brazilian Portuguese are subject to a parallel processing effect, such that marking leads to further marking and lack of marking leads to further lack of marking. For example, semantically plural verb tokens preceded by marked plural subjects in the same clause or other marked verb tokens with the same subject in the preceding discourse are more likely to be explicitly marked for plural than similar tokens preceded by unmarked subjects or verbs. This phenomenon is in direct contradiction to the principle of linguistic economy, since marking tends to occur precisely in those contexts in which it is most highly redundant and could therefore be discarded with no loss of information. Furthermore, the marking of successive plural tokens cannot be considered statistically independent events, since the outcome of previous marking decisions effects future marking. We propose that the parallel processing principle is a universal of language use.

In 1972, Labov, Yaeger, and Steiner reported a series of “near-mergers” that have since proved to be difficult to assimilate to the standard conception of the phoneme and that challenged our current understanding of how language production is related to perception and learning (Labov, Yaeger, & Steiner, 1972). In these situations, speakers consistently reported that two classes of sounds were “the same,” yet consistently differentiated them in production. Labov (1975a) suggested that this phenomenon was the explanation for two “falsely reported mergers” in the history of English, where word classes were said to have merged and afterward separated. It appears that sound change may bring two phonemes into such close approximation that semantic contrast between them is suspended for native speakers of the dialect, without necessarily leading to merger. This article reports on further observations of near-mergers, which confirm their implications for both synchronic and diachronic issues, and presents the results of experiments that show how phonemic contrast is suspended for an entire community.

In a longitudinal acquisition study of the development of the verb phrase (VP), a Trinidadian child who was exposed to both Standard English (SE) and Trinidadian English-lexicon Creole (TC) was found to use the verb forms of each system differentially according to addressee, discourse mode, semantic intent, and grammatical factors. Systematic variation was first recorded at age 2;7 and continued to develop through to the end of the study at age 4;9. School exposure to demands for SE production resulted in a decline in the child's productive TC competence overall and his movement into mid-range usage of SE and TC. The systems in contact appeared linked for the child in that he produced alternant forms from each one variably in apparent relation to his perception of the appropriate extent and range of their use. The weightings for variable constraints in each area modified over time.

We explore two unresolved methodological issues in the study of copula variation in African-American Vernacular English, assessing their quantitative and theoretical consequences via multiple variable rule analyses of data from East Palo Alto, California. The first is whether is- contraction and deletion should be considered separately from that of are. We conclude that it should not, because the quantitative conditioning is almost identical for the two forms, and a combined analysis offers analytical advantages. The second issue is whether the alternative methods that previous researchers have used to compute the incidence of “contraction” or “deletion” (“Labov Contraction and Deletion,” “Straight Contraction and Deletion,” “Romaine Contraction”) fundamentally affect the results. We conclude that they do, especially for contraction. We also discuss implications of our analysis for two related issues: the ordering of contraction and deletion in the grammar, and the presence of age-grading or change in progress in East Palo Alto.