> Specifically, I'm conceiving of an aspect that marks having the
> ability to do something. So, it would turn "to run" into "to be able
> to run". Does anyone know of an existing language (conlangs included)
> that marks any of these? If not, I nominate the terms abilitative,
> permissive, and... um, I don't know. Any suggestions for the third?

I'm surprised nobody mentioned Turkish, which also has this. In English
grammars of Turkish it is usually referred to as the "potential". The
positive is formed with the suffix -ebil. The negative, or impotential,
is formed with the suffix -eme:

Gelmek = to come (gel- = root; -mek = infinitive ending) Gelebilmek = to
be able to come Gelememek = to be unable to come

The potential endings may also be attached to negative or impotential
stem. The following examples come from G. L. Lewis' "Turkish Grammar":

Gelmiyebilirim ("come"-NEG-POT-aor-1s) = "I am able not to come", i.e.
"I don't have to come if I don't want to"

Gelemiyebilirim ("come-IMPOT-POT-aor-1s) = "I am able to be unable to
come", i.e. "I may be unable to come"

Thomas the Turcophile