In the Indo-European languages we are accustomed to a great many major structural classes, which we call 'part of speech'. These are nouns, verbs, adjectives, adverbs, prepositions, pronouns, conjunctions, and interjections. These parts of speech are sometimes formally distinguishable by their internal structure (this is particularly true in Greek and Latin), but in a language such as English the parts of speech are distinguished largely by their external distributions. In Turkish there is no such elaborate set of word classes.
- Nida (1949), Pag. 147