about prep doesn't exist in GF

Question

"He was talking about his last night."

In the previous sentence, the preposition is about, but this preposition exists neither under the prep syntax nor under the English language Morphology in RGL as shown below.

Is there is a reason for this or this preposition acts differently in different languages?

Answer 1

I don't know of any particular reason. "About" is not among the most common English prepositions like "in", "on", "for", but there are less frequent prepositions on that list, like "during", so it's not frequency based. But a list like that can never be complete, that's why we have mkPrep in the lexical paradigms for English:

mkPrep :    Str -> Prep     -- e.g. "in front of"
mkPost :    Str -> Prep     -- e.g. "ago"
noPrep :    Prep            -- no preposition

So whenever you want to use a preposition that isn't in the RGL API, just use mkPrep. In this case, mkPrep "about".