Malayalam is one of the Dravidian languages and as such has an agglutinative grammar. The word order is generally subject–object–verb, although other orders are often employed for reasons such as emphasis. Nouns are inflected for case and number, whilst verbs are conjugated for tense, mood and causativity (and also in archaic language for person, gender, number and polarity). Malayalam adjectives, adverbs, postpositions and conjunctions do not undergo any inflection; they are invariant.