A time frame of critical/sensitive periods of language development.

By a focus on three essential elements of language: phonology, semantics, and syntax, a time frame for critical/sensitive periods of language development is presented as a model of central auditory nervous system flexibility. Several studies support the hypothesis that the critical/sensitive period of phonology is from the 6th month of fetal life through the 12th month of infancy. Data indicate that the critical/sensitive periods for syntax run through the 4th year of life, and for semantics through the 15th or 16th year of life. The data indicate that there is a time dependent series of functions in sequence that is based on responsive adaptations made by the CNS to pyschophysical and electrophysiological stimuli.