For as long as modern foreign languages have been taught in British schools, French has predominated. This has remained the case despite initiatives to promote the teaching of other languages. Now, however, it is government policy to encourage diversification of first foreign language teaching, so that there will be a substantial increase in the teaching of languages other than French as first foreign languages. This paper describes the work of the Oxford Project on Diversification of First Foreign Language Teaching (OXPROD), and in particular the difficulties of setting up an investigation which takes account of pupils' language aptitude and attitude in a sample of schools. The project methodology and instruments are described, and solutions to some preliminary problems are discussed. The future development of the project is outlined.