So where is this stepping stone between one sound calls and a complex sentences? How did humans get here? Bickerton refers to the case of Genie, a girl who had had no communication with anyone due to her father imprisoning her from the age of 18 months until she was found years later at the age of 13. She had missed the critical age of of between 18 months and 3 years where she children usually acquire an adult language (see language acquisition). When she was found she didn't know how to speak English at all. Even after a long time of treatment from speech therapists and linguistic experts, she only managed to gain a very simple version of English. Her sentence's consisted of noun and verb or adjective and noun, occasional strung together and even more rarely with adverbs and certain prepositions.