In countries with a small ‘language area’, internationalization may lead to increased use of foreign languages in engineering education. This paper investigates the possible effects of learning and teaching in a foreign language. To arrive at an answer, it reviews research into the relationship between academic success and foreign language proficiency. It concludes that, for engineering programmes, learning and teaching in a foreign language will reduce the quality of education. Not only should a considerable drop in study results be expected, but also an increased workload for both students and teachers.