Impact of Differing Language Background Exposures on Bayley-III Language Assessment in a National Cohort of Children Born Less than 29 Weeks' Gestation.

Preterm infants are at risk for adverse neurodevelopmental outcomes, especially language delay. Preterm infants < 29 weeks’ gestational age, cared for in Canadian Neonatal Follow-Up Network affiliated hospitals, were assessed between 18 to 21 months corrected age using the Bayley-III. Bayley-III Language Composite Scores were compared using univariate and multivariate analyses for children in three primary language groups: English, French and other. 6146 children were included. The primary language at home was English, French or another language for 3708 children (60%), 1312 children (21%) and 1126 children (18%), respectively, and overall, 44% were exposed to two or more languages at home. Univariate analysis showed that primary language was associated with lower Bayley-III Language scores; however, multivariate analyses demonstrated that neither primary language nor language of administration were significantly associated with lower language scores when adjusted for gestational age, other developmental delays and sociodemographic factors, but multiple language exposure was. Sociodemographic and other factors are more important in determining language development than primary language at home. Further studies are needed to examine the association between exposure to multiple languages and lower Bayley-III language scores in preterm infants.