This textbook proposes a theoretical approach to linguistics in relation to teaching English. Combining research with practical classroom strategies and activities, it aims to satisfy the needs of new and experienced TESOL practitioners, helping them to understand the features of the English language and how those features impact on students in the classroom. The author provides a toolkit of strategies and practical teaching ideas to inspire and support practitioners in the classroom, encouraging reflection through regular stop-and-think tasks, so that practitioners have the opportunity to deepen their understanding and relate it to their own experience and practice. This book will appeal to students and practitioners in the fields of applied linguistics, TESOL, EAL, English language and linguistics, EAP, and business English.