A discussion of the use of the American Council on the Teaching of Foreign Languages (ACTFL) Proficiency Guidelines in teaching and testing less commonly taught languages (LCTL) describes a two-year project on that topic and looks at specific problems with four languages or language groups. The project was to familiarize LCTL teachers with the guidelines through a series of workshops, and to provide a forum for examining issues involved in adapting them for LCTL use. The languages discussed include: Arabic and the problem of diglossia, with separate standards for spoken and written language; Hindi and the issue of code-switching to and from English; Indonesian and the importance of sociolinguistic rules that are rigid and necessary to even basic proficiency in that language; and African languages and the problem of limited resources for instructional development in such a large and diverse language group. Much work remains to be done in extending the use of the guidelines beyond the commonly taught languages because of the issues not encountered in working with western languages. (MSE)