The data is drawn from a comprehensive study (in progress) of suppletion in adjectival comparatives within and beyond Indo-European. Although comparative suppletion is rare (though attested) outside of Indo-European, and although the data sample is small within any one language, the generalizations over the total data set are surprisingly robust.

The Comparative-Superlative Generalization:

If the comparative degree of an adjective is built on a suppletive root, then the superlative will also be suppletive. The superlative may use the same root as the comparative, or may be further suppletive, but will not use the basic adjectival root. Thus the schema in (1), where A, B, C refer to phonologically unrelated roots.

(1) A - A - A completely regular: short, short-er, short-est
A - B - B suppletive: bad, worse, worst
A - B - C doubly suppletive: Latin 'good': bonus - melior - optimus
A - B - A *unattested* * bad - worse - baddest

I argue that this generalization favours analyses in which the superlative is not merely related to the comparative (e.g., both involve degree operators), but is rather _derived_from_ the comparative: [[[ADJ]-COMP]-SUP] (cf. Stateva 2002 PhD UConn).

The Comparative-Change-of-State Generalization:

If the comparative degree of an adjective is built on a suppletive root, then a derived change-of-state verb (inchoative or causative) will also be suppletive. The verb may use the same root as the comparative (bad - worse - worsen; bonus - melior - meliorare), or may be further suppletive, but will not use the basic adjectival root.

By parity of reasoning to the first section, I must conclude (contra Dowty and others) that change-of-state verbs are (always) derived from the comparative, and never from the simple adjective. I will defend this view against a variety of possible objections and apparent counter-examples.