Relation between Early Vocalizations and Words

Objectives: This study investigated the relationship of phonological characteristics between early vocalizations at 6-8 months, 12-14 months, and words at 18-20 months. Additionally, we aimed to identify which phonological characteristics of early vocalization can predict speech and language development at 18-20 months. Methods: Vocalizations were collected using Language ENvironmental Analysis (LENA) from 14 children at 6-8, 12-14, and 18-20 months. Vocalizations were classified as precanonical or canonical vocalization. Words were separated from the entire vocalizations at 18-20 months. Consonant inventories and phonological structures were analyzed in early vocalizations and words. Multiple regression analysis was performed to investigate whether the rate of canonical vocalizations, the number of consonant inventories, and the number of phonological structures in early vocalization are predictive of the number of consonant inventories and the number of different words at 18-20 months. Results: Consonant inventories and phonological structures in words at 18-20 months consisted of inventories which had been produced in early vocalization at 6-8 months and 12-14 months.The results showed that the ratio of canonical vocalizations at 6-8 months predicted the number of consonant inventories and the number of different words. The number of consonant inventories at 12-14 months also predicted the number of consonant inventories in words at 18-20 months. Conclusion: This study confirmed that the phonological development of early vocalization is closely related to later speech-language development, and the speech-language evaluation based on the phonological characteristics of early vocalization can provide a basis for early diagnosis and intervention in infants and toddlers.