This book empirically examines six theories of language acquisition by considering the acquisition of French word order by instructed English-speaking learners. French and English differ in terms of word order with negation, adverbs and object clitics. These structures are examined to determine potential parameter re-setting and empirically test three Initial State theories (Organic Grammar, Full Transfer/Full Access and Modulated Structure Building) and three L2 development theories (Missing Surface Inflection Representational Deficit Hypothesis and Feature Reassembly). Oral production, comprehension and judgement data from five groups of 15 instructed English speaking learners of French ranging from beginners aged 12-13 to the high-advanced group aged 21-23 are presented. The results show significant levels of L1 transfer in the Initial State and gradual development of sentence structure. This book concludes that parameter re-setting is possible for instructed English speaking learners of French. However, learners build their syntactic representation gradually and transfer their L1 knowledge at each stage before re-setting the parameter to the French values.