Detecting Inappropriate Use of Free Online Machine Translation by Language Students – A Special Case of Plagiarism Detection

Abstract. The ready availability of free online machine translation (MT) systems has given rise to a problem in the world of language teaching in that students – especially weaker ones – use free online MT to do their translation homework. Apart from the pedagogic implications, one question of interest is whether we can devise any techniques for automatically detecting such use. This paper reports an experiment which aims to address this particular problem, using methods from the broader world of computational stylometry, plagiarism detection, text reuse, and MT evaluation. A pilot experiment comparing ‘honest’ and ‘derived ’ translations produced by 25 intermediate learners of Spanish, Italian and German is reported. 1