Generally speaking, case forms of nouns or adjectives denoting place
or place relations often develops into adverbs. These adverbs in the
next turn develope into prepositions that replace older ones.
Combinations of old prepositions and such nouns may also develope
into new adverbs and further into prepositions. This is an always
ongoing process.
The preposition "in" was at some time a locative? case form of a
noun/ajective as far as I know that denoted "inside". You still find
this stem used both as a noun/adjective and adverb in many languages.
--- In cybalist@yahoogroups.com, "ghozzis" <ghozzis@...> wrote:
> Hello,
> I would like to know if the indo-european propositions such
> as "ab", "in" etc come from nouns or not?
> Thanks
> Sacha