Oahpa! Õpi! Opiq! Developing free online programs for learning Estonian and Võro Heli Uibo author Jaak Pruulmann-Vengerfeldt author Jack Rueter author Sulev Iva author 2015-05 text Proceedings of the fourth workshop on NLP for computer-assisted language learning Elena Volodina editor Lars Borin editor Ildikó Pilán editor LiU Electronic Press Vilnius, Lithuania conference publication uibo-etal-2015-oahpa https://aclanthology.org/W15-1906/ 2015-05 51 64