In vocalizations, front vowels appear first during the reflexive stages, but back vowels appear first in the voluntary stages.
- When the tongue arches in the back we have back vowels. An example would be the vowel in the word:
- During the period of reflexive vocalizations for the baby, the vowels that will be heard most frequently are the front vowels.
- This makes some logical sense since the back of the tongue would occupied in the act of constricting the air flow for the consonants.
- Later as the child gains control over the articulators and voluntarily produces sounds, the back vowels will be heard initially more frequently. This is quite prevalent in early words like "Mama," and "Papa."