This book presents the sound structure of seven Nigerian languages– Hausa, Igbo, Yoruba, Igala, Efik, Fulfulde and Idoma. The first chapter presents a critical review of the linguistic situation in Nigeria which has an estimated over three hundred and fifty (350) languages with each language representing, as it were, a distinct ethnic group. Chapters two and three handle the issues of speech apparatus and airstream mechanisms, respectively. While giving a review of the basic principles and practice associated with the study of phonetics, it also underpins the theoretical framework of the work which leans heavily on linguistic phonetics as enunciated and discussed in Ladefoged, 1971, 1982, 2005 and Maddieson, 1984. Chapter four discusses phonation especially as it manifests in the languages studied. Chapter five identifies, classifies and discusses the segments– consonants and vowels– used in the languages indicating their combinatory possibilities and aspects of the prosody of these languages. Chapter six investigates patterns of intersegmental co-ordination in the languages while chapter seven details aspects of interference exhibited in the languages especially with regards to the English language which is still used, alongside Hausa, Igbo and Yoruba, as the official language in the country. Chapter eight has the translation of a passage in English 'the harmattan' into four of the languages studied. Phonemic transcriptions of the passage are provided as well.