Sound 32 English language 15 English 13 Juvenile literature 13 Textbooks for foreign speakers 12 Conversation and phrase books 9 Computer sound processing 8 High-fidelity sound systems 8 Grammar 7 Recording and reproducing 6 Sound recording for foreign speakers 6 Equipment and supplies 5 Self-instruction 5 Experiments 4 Methods 4 Problems, exercises, etc 4 Acoustical engineering 3 Architectural acoustics 3 French language 3 Light 3 Music 3 Study and teaching 3 Underwater acoustics 3 Absorption of sound 2 Auscultation 2 Biography 2 Chinese language 2 Computer storage devices 2 Dictionaries 2 Examinations 2