Computerized adaptive testing for language teaching and learning takes advantage of two properties of the computer: its number-crunching and multiple-branching capabilities. Adaptive testing has also been called tailored testing because it aims at presenting items that suit the student's competence and that are informative, using an item bank and an algorithm for selecting items. The most widely used theoretical framework for these components is item response theory, which allows for the measurement of the trait that corresponds to the subject's ability. Creation of the item bank includes planning, field testing, item analysis, calibration, and item inclusion. Test bank management requires additional features for updating, importing items, listing items, and obtaining item information. The item selection procedure estimates the examinee's ability after an answer and finds the next item that is most appropriate. Test administration involves gathering information about the examinee, a self-rating of general proficiency, and sub-tests using the item selection procedure. Results are available immediately, an advantage appreciated by examinees and administrators. The adaptive procedure allows for shorter tests, and the items are never too difficult or too easy. Limitations include the artificiality of the computer environment, restriction of answer type and test content, non-applicability for small-scale testing, the theoretical assumption of unidimensionality, and cost. (MSE)