This paper introduces the architecture and interface of a serious game intended for pronunciation training and assessment for Spanish students of English as second language. Users will confront a challenge consisting in the pronunciation of a minimal-pair word battery. Android ASR and TTS tools will prove useful in discerning three different pronunciation proficiency levels, ranging from basic to native. Results also provide evidence of the weaknesses and limitations of present-day technologies. These must be taken into account when defining game dynamics for pedagogical purposes.MEC-FEDER Grant TIN2014-59852-R y la Junta de Castilla y León Regional Grant VA145U1
