Reading outcomes of children with delayed early vocabulary : A follow-up from age 2–16

Background Delays in expressive vocabulary have been associated with lower outcomes in reading. Aim The aim is to conduct a long-term follow-up study to investigate if early expressive vocabulary delay (late talking) predicts reading development in participants age 16 and under. We examine further if the prediction is different in the presence of family risk for dyslexia (FR) and early receptive vocabulary delay. Methods Expressive and receptive vocabulary skills were assessed at the age of 2–2.5 years, and reading skills in Grades 2, 3, 8 and 9 (age 8–16). The longitudinal sample consisted of 200 Finnish-speaking children, of which 108 had FR for dyslexia and 92 came from families without reading difficulties. We compared the reading development of five subgroups: 1) FR and no vocabulary delay; 2) FR and late talkers, 3) FR, late talkers and co-existing receptive vocabulary delay; 4) no FR and late talkers; and 5) no FR and no vocabulary delay. Results The group with FR and expressive and receptive vocabulary delay had difficulties in reading comprehension, but not in reading fluency. The late talkers without receptive vocabulary difficulties tended to become typical readers. Conclusions and implications Delays in early vocabulary can lead to a reading comprehension deficit, with the specification that expressive vocabulary deficit alone can alleviate in time, whereas the combined deficit is a stronger risk marker.