a study by gathercole and baddeley (1989) showed the importance of sound for early word meaning. they tested the phonological memory of 4- and 5-year-old children, i.e., how well these children were able to remember a sequence of unfamiliar sounds. they found that children with better phonological memory also had larger vocabularies at both ages. moreover, phonological memory at age 4 predicted the children's vocabulary at age 5, even with earlier vocabulary and nonverbal intelligence factored out.