From childhood to old age, we all use language as a means of broadening our knowledge of ourselves and the world about us.When humans first --1--, they were like newborn children, unable to use this --2-- tool. Yet once language developed, the possibilities for human kinds future --3-- and cultural growth increased. 

Many linguists believe that evolution is --4-- for our ability to produce and use language. They --5-- that our highly evolved brain provides us --6-- an innate language ability not found in lower --7--. Proponents of this innateness theory say that our --8-- for language is inborn, but that language itself develops gradually, --9-- a function of the growth of the brain during childhood.Therefore there are critical --10-- times for language development. 

Current --11-- of innateness theory are mixed, however, evidence supporting the existence of some innate abilities is undeniable. --12--, more and more schools are discovering that foreign languages are best taught in --13-- grades.Young children often can learn several languages by being --14-- to them, while adults have a much harder time learning another language once the --15-- of their first language have become firmly fixed. 

--16-- some aspects of language are undeniably innate, language does not develop automatically in a vacuum. Children who have been --17-- from other human beings do not possess language. This demonstrates that --18-- with other human beings isnecessary for proper language development. Some linguists believe that this is even more basic to human language --19-- than any innate capacities.These theorists view language as imitative, learned behavior. --20--, children learn language from their parents by imitating them.Parents gradually shape their child’s language skills by positively reinforcing precise imitations and negatively reinforcing imprecise ones.