U-SHAPED DEVELOPMENT
A process in first and second language acquisition where a syntactic feature appears to have been acquired but is later used or formed incorrectly. Often quoted is a finding that many children use the correct irregular past tense forms in English (went, fell) but then go on to use incorrect forms in-ed (wented, goed, falled). In due course, the correct form is restored.
Initial mastery of language may well be holistic: the child acquiring inflected words as individual units without recognising the system that links, for example, walked to its stem walk. Similarly, irregular forms such as broke or went are probably first acquired as if they were simple items of vocabulary. However, at some stage, the child comes to recognise that morphology is rule-governed. Its reaction is then to over-generalise the rules it has extrapolated (‘for past tense, add-ed’), replacing irregular forms with regularised ones. In time, evidence from adult speech leads it to restrict the application of the-ed rule and to reinstate the irregular forms.
A connectionist computer program has simulated the trial-and error learning of regular and irregular past tense forms in English. The learning process manifested exactly the kind of U-shaped development that has been observed naturalistically.
See also: Over-generalisation, Syntactic development
