What are morphemes and where do they come from?
Morphemes are abstract or theoretical units of language. The reason we talk about morphemes is more for structural language analysis than anything else. A morpheme is the smallest meaningful element of language that, as a basic phonological and semantic element, cannot be reduced into smaller elements. Examples of morphemes are: book, it, long, three. Only in particular cases do morphemes actually correspond to the grammatical category word. We distinguish between free morphemes, also called bases or roots, which may have both a lexical (e.g., book, fast, red) as well as a grammatical function (e.g., and, it, out) and bound morphemes, in which it is a matter of either a lexical stem morpheme (e.g., typ- in type, typical), inflectional morphemes (e.g., verb endings), or derivational morphemes (e.g., where affixes form new words).