The genetic factor structure of a range of learning measures was explored in twin children, recruited in preschool and followed to Grade 2 ("N"?=?2,084). Measures of orthographic learning and word reading were included in the analyses to determine how these patterned with the learning processes. An exploratory factor analysis of the…

The dependence of reading on speech is based on three assumptions: speech is the primary language system, acquired naturally without direct instruction; alphabetic writing systems are more or less phonetic representations of oral language; and speech appears to be an essential foundation for the acquisition of reading ability. By presupposing…