The Word Gap (Weisleder & Fernald, 2013)

Goal

examined whether the amount of speech parents directed to their infants in low SES Spanish-speaking families affected how quickly children could process spoken words in real time and how well they learned new vocab.

They use

 the LENA recorder to collect data, wear it all day (count words automatically)

Their findings show that overheard speech

doesn’t support language development

whereas child-directed speech

plays an important role

Only the amount of CDS, not the overhead adult convo, was

correlated with children’s vocab size

heard more CDS

larger vocab size

CDS also predicted faster

speech processing speed

heard more CSD also means

faster processing speed

Speech processing speed

mediates the relationship between language input (CDS) and vocabulary size

Richer CDS input

strengthens infants’ real-time word processing skills

and these faster processing skills

help them learn words more efficiently, leading to a larger vocabulary