Socioeconomic (SES) differences in language are evident in female infants at 7months of age

Language skills, strongly linked to academic success, are known to differ by socioeconomic status (SES), with lower SES individuals performing less well than higher SES.

To examine the effect of SES on infant language at 7months of age and the relationship between maternal vocabulary skills and infant language function. To determine if the relationships between SES and infant language are mediated by maternal vocabulary skills.

Longitudinal follow-up of healthy term female African American infants born to mothers in two SES groups: Low SES (income-to-needs≤1, no education beyond high school) and Higher SES (Income-to-Needs >1, at least a high school diploma).

54 infants tested at 7months of age; 54 mothers tested at infant age 7months.

Preschool Language Scale-5 (PLS-5), Vocabulary and Matrix Reasoning subtests of the Wechsler Adult Intelligence Scale-IV.

Low SES infants (n=29) performed less well than Higher SES (n=25) on PLS-5 Total Language, Auditory Comprehension, and Expressive Communication (p≤0.012). Maternal Vocabulary subtest scores were lower in Low SES than Higher SES (p=0.002), but not related to infant PLS Language scores (p≥0.17). Maternal vocabulary did not mediate the relationship between SES and infant language skills at age 7months.

In this single sex and race cohort of healthy, term, female infants, lower SES exerted negative effects on infant language by 7months of age. While maternal vocabulary scores showed no relation with infant language skills at 7months, continued study of the relations between SES, infant outcomes and maternal characteristics is needed to determine how low SES conditions impact early language. These findings underscore the importance of early interventions, as well as policies designed to improve socioeconomic conditions for infants and families.