The document discusses morphology, which is the study of the internal structure of words. It defines morphology, words, and morphemes. Words are the smallest independent units of language, while morphemes are the smallest meaning-bearing units that make up words. There are two types of morphemes: free morphemes like nouns and verbs that can stand alone, and bound morphemes like prefixes and suffixes that cannot stand alone and modify the meaning of words. The document provides examples of different types of morphemes and how they combine to form complex words.