Researching how mathematical expression varies in different languages requires methodologies which allow investigation of languages on their own terms and the presentation of mathematical data in multiple languages. Perspectives and tools from linguistics can assist in identifying and describing mathematical expression in varied languages, particularly those without a school mathematics register. A typological approach, which deals with finding, describing and classifying languages according to their structural similarities and differences, is useful to investigate how a mathematical function or process is performed in different ways in different languages. Interactive structured tasks can elicit rich and targeted mathematical language data, where details of mathematically language are difficult to elicit through direct questions and interviewing. An interlinear morphemic gloss can be used to show more information about the structure of short texts in languages other than the publication language. Such research is an ideal forum for collaboration between mathematics education researchers and linguists.