This paper gives a detailed information on the design of the speech corpus for the purpose of developing an ASR-based pronunciation tutoring system. In the first place, assumptions on the structure of the corpus are presented. Then collection of text material, recordings and procedure of annotation of the resulting speech corpus are described. In the end, preliminary results of the analysis of pronunciation errors are discussed. They provide information which is important for ASR training and testing on the one hand, and automatic error detection on the other hand.