Development of language goes on throughout life. Language learning is truly lifelong. Speakers continue to acquire morphemes to build vocabulary, stylistic variation in syntax, and pragmatic maneuvers to meet needs that shift according to interlocutors, acquired bodies of knowledge, and altered roles. Investigators of first language development have given almost no attention to how such learning takes place, what may motivate it, and the speed with which vocabulary growth and syntactic complexity can take place beyond early childhood (but see Hoyle & Adger, 1998). The focus of this chapter is the language development of older children and young people over a relatively brief time frame within project-based environments of intense peer interaction guided by one or more adults. Situations for this learning occur within out-of-school youth-based organizations that involve young members primarily in either the arts and service or athletics with a strong focus on academics.