Language skill attrition refers to the loss of any language or portion of a language whether it be the declining use of mother tongue skills, the replacement of one language by another in language contact situations, the deterioration of language in the neurologically impaired or elderly, or the death of whole languages. In this paper, language attrition refers to the loss of those second language skills primarily acquired in classroom situations. Suggestions for restoration techniques must be based upon knowledge of the (1) rate and order of attrition, (2) differential effects of loss on different language components, (3) types of skills that resist and are most vulnerable to decay, (4) relationship between method of instruction and/or order of presentation to long term retention of second language skills, (5) role of affective factors in language retention, (6) types of behavior that will best maintain skills once they have been acquired, and (7) role of individual differences in language skill loss. Necessary research must be based on predictor and criterion variables and on hypotheses based on regression theory, affective variables related to language learning and maintenance, and normative data of linguistic features controlled by proficient language users. (JK)