universal pathway in language development

universal pathway in language development. Stage theories usually
suggest a universal path (an invariant sequence of stages) for language
development. A typical child anywhere in the world starts with cooing (playing
with the vowel sounds) at two to three months of age, changes into babbling
(consonant-vowel combinations) at four to six months, begins to use
gestures at nine to ten months, and produces first words by the first birthday.
First word combinations, known as telegraphic speech (content word combinations
with functional elements left out, such as “Mommy cookie!”) normally
appear when children are between 1.5 and 2.5 years. Meanwhile, rapid
addition of new words results in a vocabulary spurt. Grammatical rules are
being figured out, as seen in young children’s application of regular grammatical
rules to irregular exceptions (called overregularization, as in “I hurted my finger”). Later on, formal education promotes further vocabulary
growth, sentence complexity, and subtle usages. Language ability continues
to improve in early adulthood, then remains stable. It generally will
not decline until a person reaches the late sixties.