Speech perception of infants with high familial risk for dyslexia differ at the age of 6 months.

As yet relatively little is known of the earliest signs of dyslexia. We present evidence showing that the speech perception of 6-month-old infants from dyslexic families differs significantly from that of infants from control families with normal reading parents; the former group needed a significantly longer duration to categorize speech sounds as long. The same difference appeared in their dyslexic parents. This study shows that differences in categorizing speech sounds according to duration, which is crucial to intelligibility in Finnish, are a factor associated with familial risk for dyslexia already at infancy, which persists until adulthood in many of those suffering from dyslexia.