Carol Stoel- Gammon used a longitudinal study approach to examine the developmental process of children’s phonologic inventories at 15, 18, 21, and 24 months of age (Stoel- Gammon, 1985). This study followed 34 children (19 boys and 15 girls) from 9 months of age until 24 months of age. All of the participants came from English- speaking homes, passed a hearing screening, and had normal motor and cognitive development. Naturalistic language samples were collected at three month intervals at 9, 12, 15, 18, 21, and 24 months of age. The study obtained samples of prelinguistic vocalizations and meaningful speech, but was limited to analyze only the meaningful speech samples. This study determined meaningful speech as the production of at least …show more content…
Using these different forms of analysis, Stoel- Gammon determined that the phonetic inventory increases as age increases and that that inventory size is directly related to the age of onset of meaningful speech. The inventory of phonemes in the initial word position is always greater than the final word position and these inventories manner of production’s included stops, nasals, and glides; which are voiced and anterior. The evidence also shows that there is a strong similarity in the sequence of acquisition of initial and final consonants. In regards to manner, certain phones (e.g. stops) usually develop before later ones (e.g. fricatives) develop. In regards to place, it is highly probable that a child will produce an anterior sound (e.g. alveolar) before a more posterior sound (e.g. velar). Also, it is more likely that a child will produce a sound in the word- initial position before producing the same sound in the word-final position, except for /l/ and /r/ which are usually first produced in the word- final position. (Stoel- Gammon, …show more content…
The use of graphs gave a clear picture of the evidence. This research is very important to continue the understanding of phonetic inventory development in typically and atypically developing children. It makes it simpler to see what sounds children should be producing at a certain age and this can help determine goals for children who may be delayed. It would be interesting to see a similar study completed with atypical children and see if the same sounds develop in the same order, just delayed. It was also interesting to see that even though some children first produced meaningful speech later than others, at the end of the study majority of the participants had almost the same phonetic inventory. (Stoel-Gammon,