hopes, like the English "may I sleep well". It was formed with an athematic ablauting suffix -yéh₁- ~ -ih₁- attached to the zero-grade of the stem. In Vedic Sanskrit, optatives were very rarely found for characterised stems (primary and secondary derivations); most occurrences of the optative are in root verbs. This is taken by Sihler to indicate that the optative was not really a mood in PIE, but a separate verb, and was thus restricted to being derived directly from roots only, not from already-derived verbs. In addition, it appears that in PIE itself, stative verbs did not have the optative mood; it was limited to eventive verbs. Early Indo-Iranian texts mostly lack attestations of stative optative forms. Injunctive The place of the injunctive mood, of obscure function, is debated. It takes the form of the bare root in e-grade with secondary endings, without the prefixed augment that was common to forms with secondary endings in these languages. The injunctive was thus entirely without tense marking. This causes Fortson (among others) to suggest that the use of the injunctive was for gnomic expressions (as in Homer) or in otherwise timeless statements (as in Vedic). Verb formation From any particular root, verbs could be derived in a variety of means. In the most conservative Indo-European languages (e.g. Ancient Greek, Sanskrit, Tocharian, Old Irish), there is a separate set of conjugational classes for each of the tense/aspect categories, with no general relationship obtaining between the class of a given verb in one category relative to another. The oldest stages of these languages (especially Vedic Sanskrit) reveal clear remains of an even less organized system, where a given verb root might have multiple ways, or no way at all, of being conjugated in a given tense/aspect category — sometimes with meanings that differ in unpredictable ways. This clearly suggests that the tense/aspect categories originated as separate lexical verbs, part of a system of derivational morphology (compare the related verbs "to rise" and "to raise", or the abstract nouns "produce", "product", "production" derived from the verb "to produce"), and only gradually became integrated into a coherent system of inflectional morphology, which was still incomplete at the time of the proto-language. There were a variety of means by which new verbs could be derived from existing verbal roots, as well as from fully formed nominals. Most of these involved adding a suffix to the root