Many songbirds including White-crowned Sparrows Zonotrichia leucophrys learn their vocalisations from adults in the population. Given vocal tradition, some isolation and accumulation of copy errors (cultural micromutations), regional dialects arise. This talk will explore parallels in speech development and dialects in humans, and dialect development and dialect systems in birds. For example, at dialect boundaries birds are often "bilingual'' (sing two dialects). Some bird species exhibit dialect isoglosses (as in German, Austrian and Dutch dialects). Language is stored in one hemisphere in humans and birds. Both organisms require audio-sensory feedback to moderate motor output, thus deaf children and deaf birds will lisp. Both organisms learn language optimally during an early time window. Second language acquisition in both birds and humans is more effective with living teachers than with tapes or videos.