As its title suggests, this book is concerned with the use of Esperanto. In our experience, very few people know that this language really is used, in both writing and speech, and that it has found speakers all over the world. To a certain extent, even to us, it is sometimes hard to imagine that a language created by a single person at his desk has developed for more than a hundred and thirty years to become a fully fledged means of communication. It is our wish to provide insights into as many fields and ways in which Esperanto is applied as possible, and we do hope that the book will find an open-minded reader who is willing to embark on this description and to gain their own impression based on the facts that we present.The research leading to the results presented in this book received funding from the European Union's Seventh Framework Programme (grant agreement 613344, project MIME). This support is gratefully acknowledged. MIME stands for "Mobility and Inclusion in Multilingual Europe". It is a research project on multilingualism that over the four years of its operation (2014)(2015)(2016)(2017)(2018) brought together more than 70 researchers in eleven disciplines and from 22 universities and research institutes in 16 countries. The authors of this book worked in a research group dealing with the optimal use of mutually complementary strategies for communication in multilingual settings, such as translation and interpreting, the development of receptive skills within language families (so-called intercomprehension) and machine translation. Our team at the University of Leipzig was responsible for the use of lingua francas. As English is presently the language mainly associated with this term, English functioning as a lingua franca was the focus of our research, with investigations into migration and study-abroad contexts (see, for example, Fiedler & Brosch [eds.], Brosch, 2019).Because of our background as Esperanto speakers, we felt motivated to extend our studies to another language that has been used as a lingua franca, the planned language Esperanto. We were encouraged to continue this work when, in a comparison among the strategies studied within the framework of MIME as regards costs, user independence, linguistic accuracy, and inclusion, we found that some of the labels seemed to fit for English as a lingua franca, but not for Esperanto and could therefore not be verified as characteristics of a lingua franca as such. This was the starting point for exploring in more detail what the practice of Esperanto communication looks like, how successful the members of the international speech xx Esperanto -Lingua Franca and Language Community community are in the use of their language, and where we can find similarities and differences when comparing the use of English and Esperanto in comparable contexts. The results of this investigation are found in this book.The book is written in English. This choice of language was not difficult, given that English is the dominant language used to report research findi...
