Etymology

Meillet has cautiously derived from a Proto-Indo-European adverbial morpheme *-tes, comparing to adverbial forms such as Sanskrit मुखतस् ‎(mukha-tás, “from the mouth”), Latin fundi-tus ‎(“from the foundation, utterly”), in-tus ‎(“from the inside”). Alternatively, has been paralleled with Anatolian ablative instrumental endings: Luwian [script needed] ‎(-ati), Lycian [script needed] ‎(-edi, -adi). Yet another proposal going back to Bugge derives this from Proto-Indo-European *éti.