Interaction theory, like Creative Construction theory, places a large emphasis upon the input that a learner receives. The main difference however, is that in Interaction Theory, the stress is placed almost entirely upon input. In interaction theory, it is the type of input provided that is the key feature. Researchers believe that all native speakers modify their speech in conversations with non-native speakers in order to make the input comprehensible. This is done in a number of ways, including comprehension checks, paraphrasing, and clarification requests. It follows then, that if comprehensible input is the largest part of acquisition, the modified input of native speakers is responsible for language acquisition.
Studies have shown that the altered speech of natives is helpful for non-native speakers, however it has not been determined that this is the only necessary component in second language acquisition.