The following were the selection criteria: The participant (a) was between 3 and 5 years of age; (b) presented with a significant, congenital speech impairment (i.e.,<75% comprehensible to unfamiliar partners in the no context and semantic context conditions of the Index of Augmented Speech Comprehensibility in Children (Dowden, 1997); (c) had prior exposure to aided AAC; (d) had an expressive vocabulary of at least 25 words/symbols, according to caregiver report on the MacArthur Communicative Development Inventories (CDI; Fenson et al., 1993); (e) communicated using telegraphic messages (i.e., at least 90% of messages involved no more than one symbol); (f) demonstrated comprehension of at least 90% of the target graphic symbols, with multiple learning opportunities using a paired instructional paradigm provided if required (Schlosser & Lloyd, 1997); (g) successfully selected picture symbolswith90%accuracy within a field of 15 target symbols using direct selection; (h) comprehended early two-word relations with at least 80% accuracy (i.e., comprehended at least 8/10 action – object and possessor – possession relations on procedures adapted from Miller & Paul, 1995; e.g., ‘‘Show me the doll’s shoe’’); and (i) had hearing and vision within or corrected to be within functional limits, according to parental report, and, if available, medical records.