When one form replaces another over time in a changing language, the new form does not occur equally often in all linguistic contexts. Linguists have generally assumed that those contexts in which the new form is more common are those in which the form first appears and in which it advances most rapidly. However, evidence from several linguistic changes (most importantly the rise of the periphrastic auxiliary do in late Middle English) shows that the general assumption is false. Instead, at least for syntactic cases, change seems to proceed at the same rate in all contexts. Contexts change together because they are merely surface manifestations of a single underlying change in grammar. Differences in frequency of use of a new form across contexts reflect functional and stylistic factors, which are constant across time and independent of grammar.

Speaker's sex has emerged as one of the most important social factors in the quantitative study of phonological variation. However, sex does not have a uniform effect on variables or even on variables that represent sound change in progress. This is because sex is not directly related to linguistic behavior but reflects complex social practice. The correlations of sex with linguistic variables are only a reflection of the effects on linguistic behavior of gender — the complex social construction of sex — and it is in this construction that one must seek explanations for such correlations. Sociolinguists generally treat sex in terms of oppositional categories (male/female), and the effects of sex on variation are generally sought in linguistic differences between male and female speakers. However, because gender differences involve differences in orientation to other social categories, the effects of gender on linguistic behavior can show up in differences within sex groupings. Data on sound changes in progress (the Northern Cities Chain Shift) among Detroit area adolescents show that gender has a variety of effects on variables and that the significance of gender in variation cannot be reduced to notions of male or female speech as “more or less conservative.”

This article analyzes the assibilation of /r/ among young people in San Luis Potosí, Mexico, in light of previous research on women's speech in language change. It is demonstrated that assibilation, an innovation known to have first appeared in the speech of women of the middle and upper social echelons, is closely associated with sex, sociocultural level, and attitude toward traditional male and female roles. These attitudes are suggested as a factor that plays an important role in the dynamics of the change, showing opposite effects among young men and women. That is, young men with traditional attitudes assibilate least, whereas young women with traditional attitudes assibilate most frequently. Parallels between this study and one of a similar innovation in Argentinian Spanish suggest a generalized pattern of change in which variables introduced by women of the middle and upper social echelons become markers of gender display in the lower classes, where they grow to be favored by women and avoided by men. The discovery of the role of attitude toward traditional sex roles in this pattern of change is unique to the present study.

Determining the function of verbal -s in the Black English Vernacular (BEV) has been a major problem in sociolinguistics. Linguists have offered four answers to questions about the feature's origins and function, with -s seen as a case of hypercorrection, as a marker of durative/habitual aspect, as a variable marker of present tense (with the variation stemming from dialect mixture), and as a marker of historical present regardless of person and number. This article argues that confusion about -s results largely from four mistaken assumptions about it: (1) that -s did not exist in earlier varieties of BEV, (2) that the use of -s in the plural bears no relation to its use in the singular or to other processes such as the use of is as a plural or copula and auxiliary absence, (3) that -s has always functioned simply as a person/number marker in white vernaculars, and (4) that any role white vernaculars may have played in the variability of -s was a consequence of regional variation brought to the United States. This article addresses these assumptions by examining the function of -s, both in the singular and plural, and of plural is in the Cely Letters, written between 1472 and 1488, and by comparing the results to similar data in black and white vernaculars. The analysis shows that in the Cely Letters the presence of an NP subject strongly favors the occurrence of both singular and plural -s and also plural is. The same constraint operates on the same forms in older black and white vernaculars, and it affects copula and auxiliary absence as well. In the speech of younger blacks and whites, this constraint has begun to disappear as -s has become solely a marker of person/number agreement in white speech and as -s itself has disappeared in BEV.