To determine the effect of background music during classroom instruction in vocabulary and grammar and in the delivery of speeches, sophomore high school students were divided into an experimental group (66 students) and a control group (60 students). For one semester the experimental group heard classical background music during instruction, while the control group heard music only during the delivery of the first of two speeches. Measuring instruments involved were (1) Music Preference Questionnaire, (2) Vocabulary Pre-Post-Test, (3) Grammar Pre-Post-Test, (4) Measuring Instruments for the Definition Speech and the Value Speech, and (5) Background Music Questionnaire. Statistical procedures included frequency distribution tabulation of the questionnaires and the "t" test, and analysis of covariance for the vocabulary and grammar pre-post-tests. Results showed that the use of background music during classroom instruction has a beneficial effect on vocabulary and grammar learning, and that, generally, students prefer classroom background music. (Author/JMC)