There is a large body of literature investigating how the learning of a dialect feature may be conditioned by age of arrival and parental input: analysing when a child has to move to an area to acquire the dialect feature like a ‘native speaker’ and whether this is affected by one or both of the parents being speakers of that dialect. It is generally accepted that young children under 7 years of age better acquire a second dialect than older children (Chambers, 1992; Payne, 1976), and that a child should have at least one parent, or more specifically a mother, who speaks the second dialect in order to fully acquire the complex features (Payne, 1976; Trudgill, 1986). Much variability exists, particularly among those who have partially acquired these complex features: attempts have been made, with varying success to attribute this variation to sibling order or day-care (Starks & Bayard, 2002; Chambers, 1992; Kerswill, 1994). The focus of the current study, the Scottish Vowel Length Rule (SVLR) involves several conditioning factors, phonological, morphological and lexical. As such it would appear to be a complex rule that would be incompletely acquired by children with non-local parents, and those who have migrated to the local area, and detailed examination of acquisition of the rule will attempt to address unresolved issues in the field, to be later discussed.