“…To ensure that the vocabulary was appropriate for the age groups used in this study, we compiled 60 sentences from ones used in pre- Kenworthy, Klee, & Tharpe, 1990;Stelmachowicz, Hoover, Lewis, Kortekaas, & Pittman, 2000). Naturally produced tokens of four-word sentences (e.g., "I wrecked my bike," "Let me have it") were spoken by an adult male talker.…”