A consistent finding in second language acquisition research has been that in the early stages of acquisition learners often receive simplified input. This finding has led researchers to question whether or not simplified input has a facilitative effect on the acquisition process. This study examines the effects of simplified input in early L2 acquisition by experimentally manipulating language input to two groups of learners and then assessing their acquisition longitudinally within a controlled laboratory setting. The impetus for the study described here was Givón's (1990) competition hypothesis that posits that, in early L2 acquisition, vocabulary and grammar compete for memory, attention, and processing capacity. Because one can communicate with vocabulary in absence of grammar but not vice versa, it was proposed that learners receiving pidgin input would acquire vocabulary more efficiently than learners challenged with the dual task of acquiring vocabulary and grammar simultaneously. Furthermore, it was hypothesized that once vocabulary processing skills were automated, learners would acquire grammar more rapidly. Results of a variety of measures reveal that the dual task of acquiring vocabulary and grammar does not hinder either and that the longer the exposure to grammatical input the greater the advantage in real-time grammar processing abilities. Converging evidence from all measures of language learning provides strong support for the usefulness and viability of laboratory study of SLA.