urubu

Pliny the Elder was his uncle.

It's not a common word. Reading it as normal German you would understand it as "obviousness, plainness, evidentness" (from 'offenbar' = 'obvious, plain to see'; 'openable' would be 'öffenbar'). But Heideggerian can obviously be quite distinct from standard German usage, to put it mildly.

This is a directory of available multilingual corpora:

http://opus.lingfil.uu.se/

Listening to languages I'm vaguely familiar with - I also like the BBC in Persian and Hausa - seems to have become part of my evening routine (I work as a technical translator). I learned Esperanto on a whim in uni in the 80s but haven't used it actively ever since.

China Radio International still has daily transmissions on shortwave. I listened to one yesterday night, as it happens.

I think you mean Wittgenstein, not Goethe ("Die Grenzen meiner Sprache bedeuten die Grenzen meiner Welt" Tractatus logico-philosophicus 5.6).

Looks like someone has successfully reinvented Zwicky's morphological box.