The development of language skills follows a series of developmental stages, which progresses by the age of 3 to 4 years. The vocabulary starts by the 12th month after birth, which includes a 5 to 10 word repertoire. An adult vocabulary consists of more than 50 000 words.
Cortical thinning related to vocabulary is correlated with development of language, while the cortical thickening (of Broca’s area) is related to phonological processing.
Thus, the blanks can be filled with vocabulary; phonological processing.