The articulation of the consonant sounds /[voiceless dental fricative]/ and /[voiced dental fricative]/ of the English language is a serious pronunciation problem for the Bechari students in general and EFL students at Tahri Mohamed University (UTMB) in particular. It was noticed that EFL students at UTMB manage to use the /t/ and /d/ sounds instead of /[voiceless dental fricative]/ and /[voiced dental fricative]/; and thus changing the meaning of words, which boil down to mean that it can create breakdowns in communication. Mother tongue interference and lack of professional instruction are some of the causes that lead to the mispronunciation of sounds. The aim of this study is to explore the causes of the constant mispronunciation of the English consonant sounds /[voiceless dental fricative]/ and /[voiced dental fricative]/ by EFL students at UTMB besides showing the importance of pronunciation Teaching.