Morphology is the study of word structure and formation. It analyzes the smallest units of meaning called morphemes, which can be free-standing words or bound within words. Free morphemes like "girl" can stand alone, while bound morphemes like suffixes are attached to other morphemes and cannot be used independently. Derivational morphology examines how new words are created through the addition of affixes, either prefixes added to the beginning of words or suffixes added to the end, altering the base word's meaning in systematic ways.