 Prominent researchers of the topic include Suzanne Flynn of MIT, Bonnie Schwartz of University of Hawaii, Antonella Sorace of University of Edinburgh, and Lydia White of McGill University.In the late 1960s-early 1970s researchers observed that the language and errors of L2 learners were not random but systematic and evidence of rule-governed behaviour.From this observation researchers proposed the concept of interlanguage which refers to the language system used by L2 learners that contains interacting linguistic aspects of both the L1 and L2.