A dynamic systems Theory perspective of second language acquisition views the process of a learner's inter-language development as non-linear, and subject to variation due to its dynamic interaction between external and internal factors in an individual learner's language system. This study investigated the intra-individual learner variation in L2 writing of one learner of English on an intensive English course over a period of four week the arm of this study is to investigate the effect of intensive exposure and interaction with the target language on variation in complexity, accuracy and fluency of L2 writing from a DST perspective.