How to access translation strings?

Where would be the most official data source to extract translated strings for:

1. Entity names (and descriptions?)
2. Attribute names (and descriptions?)
3. Enumeration values (and descriptions?)

Also, I wonder if there is such a thing as translated pset/props, because that would 1) make it easier for non-English speakers to use standard psets but at the same time 2) mask the original actual name, so the UI would have to be careful to mention that its translated.

1. Pset/qto names (and descriptions?)
2. Property/quantity names (and descriptions?)