[It's really confusing when you start new threads by replying to stuff
deep in old threads, BTW.]

E f+AOk-sto Gary Shannon <[log in to unmask]>:
> It's interesting that there can sometimes be more than
> one "opposite" to a word.  While I was atempting to
> discover which verb roots are necessary and which can
> be formed by a negating prefix on the root, I noticed
> that I need two different negating prefixes, one for
> "un" and one for "not".
> consider these opposites:
> take <-> not take (refuse)
> take <-> untake (give)
> make <-> not make
> make <-> unmake (destroy)
> know <-> not know
> know <-> unknow (forget)
> do <-> not do
> do <-> undo
> This seems more like the three points of a triangle
> than the two endpoints of a single spectrum.

The verbal prefix un- is not a generic negative marker.  It's a marker
that (in ordinary speech) can only be applied to a small subset of English
verbs (which verbs it can apply to is actually the standard example of a
cryptotype, or covert category: verbs of putting on, folding up, etc.,
which doesn't seem like an important set of verbs, but actually has
grammatical relevance in this case).  Its purpose means to restore to the
state before its un-"un-"marked verb by performing the opposite action.

> Yet in other cases these two different opposites really mean about the
> same thing:
> welcome <-> not welcome
> welcome <-> unwelcome
> happy <-> not happy
> happy <-> unhappy
> In other cases they mean three different points along
> a single line:
> fast <-> not fast (but not necessarily slow either)
> fast <-> slow

The adjectival prefix un- does produce adjectives equivalent to "not X"
(but not necessarily "the opposite of X").  And offhand I'm pretty sure it
can only apply to adjectives derived from nouns or verbs.

IOW, English negation isn't universal.  Logical negation ("not X"
literally) might be, but in derivations you're likely to have entirely
different rules from both logic and English as to what can be negated, how
things negate, and what the negations actually mean.

--                  E jer savne zarj+AOk- mas ne     Se imn+AOk- koone'f metha      Brissve m+AOk- kol+AOk- ad+AOI-.