This paper deals with the use of modal verbs in English which is one of the most complicated topics for Russian mother tongue students learning English as a second language. The problem is caused by the fact that the English language, and in this case American English, has a more sophisticated set of modal verbs in comparison with Russian. Due to cultural specificity, the category of modality plays a more important role in the English language especially in different registers including legal discourse. As is the case with many areas in translation, the different cultural contexts and in this example American and Russian legal discourse mean that there are no direct equivalents of modals. Consequently, the classroom teaching needs to focus less on the form or syntax of modal construction but more towards the semantic and pragmatic meanings of modals within defined cultural contexts. We suggest using legal documents as a resource for teaching and learning English modal verbs and applying a constructivist approach [1-5 and others] for their analysis in the language classroom. By adopting a constructivist approach to the analysis of legal texts, the law students become involved in linguistic analysis and research. A constructivist approach encourages them to create and discover knowledge, rather than receive it, to think, analyse, and reflect, rather than accumulate and memorise. As a result, it makes the process of teaching and learning more active and gives students new opportunities to improve their linguistic competence as well as their skills in the practical translation of legislative texts. The results of this study can find their application in the teaching of English for Special Purposes as well as the theory and practice of translation.