ABSTRACT
Ergative-absolutive languages mark the subject of a transitive verb with the ergative case and the direct object with the absolutive case. The case marking in Tibetan simply operates on a different system from English. The most common thematic roles are agent, theme, experiencer, goal, source, instrumental, beneficiary, etc. It is generally assumed that universally each noun phrase in a sentence has a grammatical case. It is also assumed from a semantic perspective, that each noun phrase must also have its own thematic role. In English, case is associated with syntactic position, which is why the subject of a tensed clause always gets the nominative case regardless of its thematic role. The agent is marked with the ergative case and the theme with the absolutive case. Classical Tibetan employs four inflectional forms for verbs: future, present, past, and imperative. The tenses are not in an absolute temporal sense like English but function in a relative way.
