> ..my thesis that in all IE languages,
> the comparative and superlative of 'Good' and 'Bad' are always formed
> from another stem.
> Can anyone prove or disprove this statement?
Strictly speaking, it could only be disproved, not proved, since we do not
yet know all IE languages. Evidence may emerge for some of the weirdier
ones which are still badly known.
Modern Greek is sufficient to disprove it: "good": simplex: kalos,
comparative kaliteros (written with ypsilon).
More importantly, why does it matter? If all IE languages inherit a
suppletive system, they might all retain it, or some might regularise it.
Neither seems to me significant - so where does your interest lie?
Peter