But, how does systematic variability develop? What does it look like?
Variation in Adult Input to Children
Foulkes, Docherty and Watt (1999) note that variation in the input to young speakers can “enhance the movement from the holistic word level of representation to segmental awareness by producing allophonic examples, which “may serve to highlight the location of permutable components of words.”
Wassink, Wright and Franklin (2005)
Sound elements used contrastively in the [Jamaican Creole] language system were manipulated to the greatest extent in child-directed speech, while non-contrastive elements were used to enhance understanding in speech directed to adults.
Difficulties Obtaining Child Speech
Chevrot, et al. (2000), Roberts (2002)
Developmental variation due to differences in physiological and cognitive maturation
Distinguishing word-by-word (“lexical”) learning from rule-based learning
Testing difficulties: attentional fluctuation (often resulting in insufficient amounts of data to be representative of the speaker)
Low intelligibility of utterances (less so for preschool age)
Possibility of DIFFERENT stylistic or social goals (different form-meaning mapping than in adults)
Categorical features first
Vernacular (=dialectal) forms predicted to be acquired LATE in adolescence (10-12)
Standard forms acquired later (around age 14) under contact with other members of the linguistic community outside of their friends and family.
“By the age of six a child exposed to English will have constructed the grammar of his language. This does not mean that no further development of his knowledge of language is possible. ...We also learn certain less usual constructions of the language. These exceptional or marked patterns of the language are not taken to be part of the core grammar of the language, they belong to the marked periphery of the grammar and may be acquired later. The native speaker will also have to learn all of the social or cultural conventions associated with his language, for instance, that certain words belong to a very high style whereas others are informal. These conventions are not part of the grammar, they belong to the more general domain of human behavior.” (Haegeman 2005, p. 17)
Crosslinguistic Evidence: studies of acquisition of variability in children
For what ages has systematic variation been found?
Fischer (1958) British English (t,d), (-ing): social variation ages 3-10
Roberts (1994, 1996, 1997) American English (Philadelphia variety), (t,d): both, ages 3-4
Children do acquire socially-influenced variable patterns prior to adolescence
Children become socially competent language users early--as they acquire language
Simultaneity of acquisition of variable and categorical features makes it difficult to defend a view that sociolinguistic competence vis a vis acquisition of variation is layered on top of or follows “basic acquisition.”
Adult-modeled variation may be instructive for learning styles