This book reports the proceedings of the conference on the role of speech in language, the fifth conference in the "Communicating by Language" Series, sponsored by the Growth and Development Branch of the National Institute of Child Health and Human Development. The focus of the first group of papers is on the development of speech in man and child. The papers cover such topics as the origin of speech from animal sounds, symbols inside and outside of language, the evolution of speech and its human aspect, the movement from syllables to phonemes, phonetic feature analyzers and processing the speech of infants, developmental aspects of speech perception, and the interrelatedness of speech and language. The second group of papers concentrates on the area of language without speech, with discussions of sign language and its structure, including the encoding of information in sign language. The relationship between phonology and language is the topic of the third section, with papers concerning sound and its absence in the linguistic symbol, the role of phonology in language, and a discussion of the parallels in phonological and semantactic organization. The final paper, "Speech, Language and Communication," serves as a summary of the conference. (CLK)