The study examined linguistic flexibility of Hebrew-speaking students from middle childhood to adolescence compared with adults on tasks requiring them to alternate between different versions of varied linguistic stimuli. Lexical flexibility was tested by constructing different words with a shared root and a shared prosodic template; Hebrew-specific morpho-syntactic abilities were tested by alternating between bound inflected and free syntactic forms of verbs and nouns; syntactic tasks involved shifting between direct and indirect speech, between single-clause and bi-clausal sentences with subordinate or coordinate clauses, and construction of well-formed sentences from scrambled groups of words. Across the board, participants encountered more difficulty in shifting from low frequency, high-register, structurally more fused constructions typical of written usage to their everyday, more transparent options than vice versa. High-school adolescents responded like the adults on most tasks, differing significantly from grade-school and junior-high-school students. These results are interpreted in terms of linguistic and developmental variables underlying the protracted path to acquisition of high-level linguistic flexibility.