Phonetic annotation of a non-native speech corpus

Annotating non-native speech on a phonetic level is an extremely labour-intensive task and therefore requires a proper balance between the expected benefit and the resources needed. This paper reports on the experience gained when collecting and annotating a corpus of English sentences recorded by students with Italian and German as their mother tongue. The annotated data were used intensively during the development phase of a language learning tool, which allows automatic diagnosis of pronunciation errors and gives corrective feedback to the learner. Suggestions for further improvement in the annotation procedure will be presented, based on the experience acquired in creating the corpus.