Abstract
Although linguists in general have always been aware of the importance of words, morphology, or the study of the internal structure of words, did not emerge as a distinct sub-branch of linguistics until the nineteenth century. Its importance, nevertheless, has always been assumed, as attested by its central role in Panini's fourth-century BC grammar of Sanskrit, and more recently in Chomsky and Halle’s (1968) ground work “The Sound Patterns of English”. In this study the focus is on the study of the internal structure of English words and all the processes which can be applied to these words to derive new words. Knowing the structure of words will help the students understand the meaning of words through their internal make up, and will undoubtedly enhance the students’ competence in the language. This will help the students to master word constituency, to know which part of speech a word belongs to and to divide it into its component parts. For instance, a student will be able to recognize that a complex noun usually ends in -ence, -hood, -ment and a verb may have the affixes de-, en-, -ize attached to it and an adjective may have the affixes –ic, –ive, -al . This study incorporates five chapters. The first is an introductory chapter and it includes four components: Introduction, Aims of Study, Hypothesis and Methodology. The second chapter is devoted to discussing basic definitions of the term word and the term morpheme. It also introduces a comparison between bound and free morphemes. The third chapter sheds light on affixation in general, types of affixation and their sub-divisions. It discusses derivational and inflectional affixes, prefixes and suffixes. It also deals with lexical categories which are nouns, verbs, adjectives, adverbs and prepositions and also focuses on other functional categories such as determiners, auxiliaries, pronouns, co-ordinating conjunctions and complementisers. The study attempts to show the relationship between functional words which belong to classes known as functional categories and content words which belong to classes known as lexical categories. The fourth chapter deals with the relationship between teaching vocabulary and affixation and shows how students can become more competent when they learn new vocabulary. It focuses on the methods followed in teaching affixation and whether they are appropriated or not in teaching affixation to Libyan learners of English. Finally, chapter five focuses on the applied aspect of teaching affixation to Libyan learners of English and presents statistics of a test which was set to some learners.