If second-language errors cannot be accounted for on the basis of interference from the mother tongue, from what source do the errors originate? The answer the researchers give is that they are not interlanguage errors, but intralanguage errors. An intralanguage error is not the result of conflict with the native language but the result of some problem in the acquisition of the second language itself. Intralanguage errors arise from the lack of congruity between the second-language learner's set of language rules and those of the native speaker. These errors are termed developmental or restructuring errors because they are the direct result of the learners' attempts to create language based on their hypotheses about the language system they are learning. In a study by Dulay and Burt (1973), 85 percent of the errors among second- language learners were developmental. Another study by Dulay and Burt (1974) reported that child speakers of Chinese and Spanish acquired eleven English structures in the same sequence, thus providing research support for the thesis that strategies for all learners are similar and that the mother tongue is not the major influence in second-language learning.
The data seem to imply that second-language learners approach language learning much as first-language learners do. That is, they formulate a self- created interim language system, practice "creative construction," and then compare the results with the feedback they receive from the language around them. According to Dulay and Burt, both first- and second-language learning involve the same two internal processes: "creative construction" and testing of hypotheses about the language (Ott et a!., 1973). Studies by Dulay and Burt (1973) support the belief that all language learners all over the world use similar learning strategies, and that these strategies control the order of acquisition of syntactical structures.
The conclusions drawn in the preceding paragraphs have been derived from studies of child second-language learners, adult second-language learners, and first-language learners. Researchers have found that errors in first- and second-language learning are predictable but that the errors are different. In both cases the errors result from learner-created rules which are then tested and revised by the learner. It was found that learners corrected intralanguage errors sooner than interlanguage errors (Scott & Tucker, 1974).