On Indo-European superlative suffixes

Abstract The goal of this paper is to provide some insights into the degree morphology of the ancient IE languages, specifically the superlative suffixes *‑is-toand *‑is- ̊mo-, which have a wider dialectal distribution and could go back to PIE. The relationship of those superlative suffixes to ordinal suffixes is known, but its nature has not been appropriately explained. The suffixes *‑to- and *‑mo- must have originated in the ordinals as thematic formations derived from cardinals and then expanded to the superlatives through the ordinal ‘first’ and other semantically related adjectives (‘last’ and polar/spatial adjectives). Those words provide the semantic and combinatory links between ordinals and superlatives that account for the shared morphology, as the textual evidence also proves. The use of *‑to- and *‑mo- in all those words across the Indo-European languages shows a systematic correlation. The suffixes *‑is-to- and *‑is- ̊mo- are a nice example of transparent nesting, since both include the zero-grade of the comparative suffix. They must have started as relative superlatives, given that ‘first’, ‘last’ and the other related words cannot be absolute superlatives. This is in accordance with a general tendency of evolution of the expressions of the superlative degree.