Do experimental measures of word learning predict vocabulary development over time? A study of children from grade 3 to 4

• We tested whether measures of word learning predict vocabulary development over time.
• Measures of existing vocabulary and word learning were administered to 90 children.
• The vocabulary development was measured over a period of 9 months from grade 3 to 4.
• Performance on phonological word learning measures predicted vocabulary development.
• Initial evidence of the predictive validity of phonological word learning measures was provided.

Experimental measures have been used in several studies to simulate real word learning over time. The main purpose of the present study was to investigate whether such measures actually predict vocabulary development over time. Ninety grade 3 children were given experimental measures designed to assess phonological and semantic aspects of learning of novel words together with traditional measures of vocabulary and general cognitive ability. The vocabulary measures were administered nine months later to the same children in grade 4. Experimental measures of phonological aspects of word learning were found to contribute to the prediction of the children's vocabulary in grade 4 over and above their vocabulary and general cognitive ability in grade 3. A measure of semantic aspects of word learning did not contribute further to the prediction of vocabulary growth. The study provides initial evidence of the predictive validity of phonological measures of word learning.