The present study examined the pattern of deletion of final /t/ and /d/ in word final consonant clusters in sixteen three- and four-year-old children and their degree of mastery of phonological and grammatical constraints to answer the following questions: how and when is this variable rule acquired, and how does its acquisition relate to the learning of the categorical rule of past tense formation? Sixteen children were tape recorded in their South Philadelphia day care centre. In addition, eight of their mothers were interviewed in their homes for purposes of comparison.Results of the study revealed that children as young as three had, for the most part, mastered the phonological constraints on (-t, d) deletion. They matched the adult pattern including the constraint of following pause disfavouring deletion, the only one that has been shown to vary according to geographical dialect. The children also made a consistent and adult-like distinction between the grammatical forms of monomorpheme and weak past tense. Their high rate of deletion in semi-weak verbs, which differs from adult patterns, suggests that the children are demonstrating rule acquisition based on an analysis of verbal inflection.

Expressive language outcomes measured by MLU and the Index of Productive Syntax (IPSyn) at ages 3;0 and 4;0 were investigated in 34 late talkers with normal receptive language identified between 2;0 to 2;7 and 16 typically developing comparison children matched on age, SES, and nonverbal ability. Late talkers made greater gains than comparison children between 3;0 and 4;0 in both MLU and IPSyn raw score. However, when age-standardized z-scores were analysed, the late talkers were about 2·5 standard deviations below comparison children on both measures at both ages. At 3;0, 41% of the late talkers had MLUs above the 10th percentile based on Scarborough's (1990) benchmark sample; by 4;0, 71% did so. Using the IPSyn, a more stringent measure, 34% scored above the 10th percentile at 3;0 and only 29% did so at 4;0. MLU was significantly correlated with the IPSyn at both ages for the late talkers, but only at 3;0 for the comparison children. A converging set of regression analyses indicated no group differences in the predictive relationship between MLU and IPSyn, suggesting that the late talkers were delayed on both measures but not deviant in their development.

Recent work in the acquisition of variation has shown that children begin to learn patterns of stable variation at a very early age. In fact, it appears that they acquire variable rules at about the same time as they are acquiring related categorical rules. Little is known, however, about the transmission from generation to generation of features undergoing sound change in progress. Therefore, this study examines the acquisition of the Philadelphia short a pattern by 18 3- and 4-year-old children. Even though this pattern of the raising and tensing of short a is a complex one, the children had, for the most part, acquired it. In almost all cases, the children matched the short a distribution both of their parents and a group of adult Philadelphians who were interviewed in the mid 1970s and described in Labov (1989b). These results indicate that even the youngest members of the speech community are actively participating in ongoing sound change.

Late talkers with normal receptive language and typically developing peers matched at 24- to 31-month intake on socieoeconomic status and nonverbal cognitive skills were compared at age 3 (N = 29, 20) and age 4 (N = 37, 16) on grammatical morpheme suppliance during speech samples. Age 4 late talkers differed from age 3 MLU-matched typically developing children on only the contractible copula. At age 4, "late bloomers" did not differ from typically developing children on any morpheme, but late talkers with "continuing delay" differed from comparison children on articles, nominative case pronouns, auxiliary be, and the contractible copula. Noun phrase morphemes were acquired earlier than verb phrase morphemes by both late talkers and comparison children, a nominal-verbal morpheme "decalage" that was first reported by R. Brown (1973). Results suggested that our late talkers did not have a selective deficit in verb morphology relative to their MLU. Findings are discussed in terms of a spectrum of SLI, with both late talkers and preschoolers with SLI hypothesized to have weaker endowments for language learning than typically developing children, but with late talkers being less impaired and thus closer to normal on this spectrum.

Glottalization is a well-researched variable most often noted in Great Britain and Ireland but rarely in North America. The current study examines this phenomenon in a rural region of northwestern Vermont in which the dialect is popularly thought to be dying out. Forty-seven Vermonters, aged 3-80 years, were interviewed and recorded. Glottalized tokens of /t/ were coded perceptually and classified according to position in word and phonological environment. Social factors comprised age and sex. Results revealed that, unlike some vowel features historically associated with the region, glottalization appears to be a robust feature of Vermont speech. Younger speakers, particularly the adolescents, showed the highest rate of glottalization. However, differences in the patterning of the feature in different age groups begs the question of whether the glottalization in the speech of the younger speakers is, in fact, the same feature as that heard in the oldest speakers in the study or a new, less local variant. Finally, the importance of combining accounts of linguistic behavior to allow for better interpretation of data is discussed. In this study, phonetic, historical, and sociocultural information were all utilized in the interpretation of the findings, as none presented a convincing interpretation alone.