- Vocalizations/speech sample protocol: The samples will be elicited by presenting the child with a set of age-appropriate toys with lexical labels that have phonemes representing early consonant productions and the entire vowel quadrilateral. Additionally, for children who are beginning to combine consonant and vowel productions and likely to be between 18 and 29 months of age, we will use the assessment words included in previous research conducted by Preisser, Hodson and Paden (1988). This word list assesses 20 consonants, and all classes of phonemes, plus 10 consonant clusters. The words will be elicited by objects or questions. Elicited productions will be transcribed using broad International Phonetic Alphabet transcription. A number of analyses will be completed in order to describe the patterns of speech acquisition. We will use independent analyses (Stoel-Gammon & Dunn, 1985), allowing us to describe the sounds and syllable structures produced by each child.