Since the difference between one word and another is often the difference of a single sound, it is obvious that slovenly pronunciation of words may result in lowered intelligibility. Four experiments designed to investigate effects of training in pronunciation and articulation are discussed. Results indicate that training to pronounce accurately and clearly produces increased intelligibility. Instructions to stress final consonants resulted in increased intelligibility when the T-17 hand held microphone was used, but not when the T-30 throat or ANB-M-C1 mask microphones were used. No gains in intelligibility were shown as a result of instruction to stress sibilant sounds. Loudness of speech signal was not changed by this training.