Slavic languages tend to be mixed-aspectual, as well. There are two forms of most verbs: the imperfective and perfective; each of these forms can be put into the various tenses and moods. In general, the perfective is formed from the imperfective by adding a prefix. For example, in Russian, pisat' is the imperfective form of `to write', while napisat' is the perfective. While many Indo-European languages (e.g., Latin, Greek, French, the Slavic languages) have inflexional aspect (i.e., aspect is determined by the morphological form of the verb), many do not. Although Sanskrit has what are called perfect, imperfect, and aorist verb forms, the different forms do not in fact indicate differing aspect in the Classical form of the language. Even in earlier forms of Indic (e.g. Vedic), the aspect does not match the name Western linguists give the form---the names come from correspondences with the morphology of Ancient Greek.