What's the reason for the use of different non-related comparative/superlative suffixes, like *-yo(:)s, -is , opposite to *-(t)ero-; and *-is-tHo- to *-(t)mo ?
The analysis of these suffixes can be used to determinate the relationship between IE languages? For example, Celtic and Italic share the same *-isamo suffix...
JS Lopes
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