A longitudinal study investigated the claim that phonological memory contributes to
vocabulary acquisition in young children. In the first phase, children were given tests of receptive
vocabulary, receptive grammar, nonword repetition, phonological sensitivity (or
“awareness”), and performance IQ. In the second phase, children were given the
nonword repetition and receptive vocabulary tests. In Session 1, both nonword repetition and
phonological sensitivity accounted for variation in receptive vocabulary and grammar after
performance IQ effects were controlled. When phonological sensitivity was also controlled,
nonword repetition did not account for significant additional variation in receptive vocabulary and
grammar. When performance IQ and autoregression effects were controlled, all Session 1 verbal
ability measures predicted Session 2 vocabulary, but only Session 1 vocabulary predicted Session
2 nonword repetition. When phonological sensitivity was also controlled, Session 1 nonword
repetition (leniently scored) predicted Session 2 vocabulary. Overall, these findings show qualified
support for the claim that the capacity component of nonword repetition contributes directly to
vocabulary in young children. They suggest that the association between nonword repetition and
vocabulary in young children may, to a substantial extent, reflect a latent phonological processing
ability that is also manifest in phonological sensitivity.