Grammaticalization of the Lithuanian comparative "-jau(s)"

When analysing Old Lithuanian texts from the 16th and the first half of the 17th century, one can notice that comparatives with the -jaus suffix tend to appear in comparative constructions with connectives containing negation, e.g. Bet esch daugiaus dirbau / neig kursai isch yũ (VEE 102: 16-17) ‘but I laboured more abundantly than they all’ (1 Corinthians 15: 10). This is the "particle comparative" in Stassen’s terms (1985, 2001). On the other hand, authors avoided comparatives with the -jaus suffix in other types of comparative constructions (with the preposition už and the genitive). Philological and etymological analysis of neg(i) and nei(gi) ‘than’ shows that these connectives developed out of former sentence negations. This sheds some light on the syntactic environment in which the grammaticalization of the comparative suffix -jaus occurred. The Lithuanian comparative suffix -jaũ (OLith. -jau-s, e.g. geriaus ‘better’) goes back to the postponed focus particle -jaũ, which functions as a marker of EMPHATIC ASSERTION OF IDENTITY (König 1991). The primary contrastive function of the ﷓jau-s suffix can be compared to the Old Greek -τερος (Old Indic -taraḥ) in such usage as δεξίτερος ‘right(-hand)’. The grammaticalization of the focus marker jau(s) has occurred in sentences consisting of juxtaposed and contrasted clauses – the "conjoined comparative" in Stassen’s terms (Stassen 1985: 38, 44), and in these sentences, -jaus filled the role of pragmatic marker and focalizer, emphasizing one of two compared, oppositive items.