David Crystal, "The Cambridge Encyclopedia of the English Language"(Repost)

This attractive resource is organized thematically in segments covering the history of the English language (Old English, Middle English, Modern English, English in different parts of the world); English vocabulary (its nature, structure, sources, etymology, and the dimensions of the lexicon); English grammar (structure of words and sentences, definitions of the main branches of grammar); spoken and written English; English usage (varieties of discourse and regional, social, and personal usage variations); and how people learn English and new ways to study English. Appendixes include a glossary, a list of symbols and abbreviations, references and addresses, further readings, and indexes of names, items, and topics.