Olana, T. and Teshome, Z. 2015. EFL Teachers’ ’ Productive Skills Errors and their t Effects on Students’ English Language Proficiency: The Case of Selected Preparatory Schools in East Wollega Zone. Journal of Science, Technology and Arts Research. 4, 4 (Dec. 2015), 164–173. DOI:https://doi.org/10.4314/star.v4i4.21.