Over the last three decades, the standards of English in Cameroon as well as the performance of students in the English language at the General Certificate of Education (GCE) examination have been on a steady decline. While many Cameroonians keep making their way into the English language teaching industry as a result of the rapid expansion of English as a global lingua franca, the quality of language input administered to learners seems to leave much to desire. Thus, although a number of studies have attributed the continuous downward spiralling of standards to a variety of reasons, this study set out to investigate the extent to which teachers of English as a second language (ESL) in Cameroon master the language they teach, as a demonstration that the teacher is one of the major problems to be addressed. Our main objectives were to test teachers' language skills. Employing the Homogeneous Purposive Sampling Technique, a total of 40 ESL teachers in Tiko and Buea Sub-divisions of the South West Region of Cameroon were investigated using questionnaires and interviews. Of the 40, 36 showed difficulties with spelling, 33 with punctuation, 30 with pronunciation, 28 with capitalization, 27 with sentence construction, and five with agreement.