We introduce the idea of bilingual reading, where a document comes in two languages and the reader can choose at will on which language to focus during the reading. Between the complete ignorance of a language (where translation is the only option) and bilingualism (where translation is useless), there exists a variety of contexts of partial bilingualism where bilingual reading interfaces would prove highly useful. We first study through interviews and reviews how the bilingual reading experience is understood today. We provide an analysis framework and highlight design challenges for the design of bilingual reading appliances. We then describe a taxonomy of the different approaches available to address these challenges, analyze them in the light of our framework and show how they can be derived to sketch future bilingual reading interfaces.