The current fundamental changes in science and education worldwide are having an impact on the use of languages, including in doctoral studies. English is dominant and this means student-researchers are often writing in a second or even third or fourth language. The languages of disciplines are also changing, as are the practices in different countries. This chapter analyses the considerable variation in the six case studies, from an Anglophone university to a multilingual university and variations in-between. Three distinctive themes emerged from the six cases: language of the discipline, the role of English, and multilingualism in research. Students explain how intensive reading and writing, often with the help of other students, is the main strategy for acquiring the language of the discipline. The role of English is evolving. Universities are striving for a comfortable balance between language diversity and unity, with English becoming the lingua franca. In many cases, research is also multilingual as student researchers collect data in a language other than the one they report in, for example. Being able to work in several languages is important and an advantage, but is at the same time very demanding. Language competences and linguistic norms and expectations are thus significant issues of which doctoral researchers are very aware, and their attitudes to English are sensitive to the dangers of the dominance of English. In sum, the question of language or multilingualism needs much more attention in policy development than is currently the case. Not only does the discourse on the internationalization of higher education neglect this topic, but also supervisors and supervisees feel more or less alone.