On ebay, I found this computer, which is either still not sold for almost a year or re-offered.
It was also mentioned in this thread, they didn’t know what is is (although the label and parts suggest that this is a language lab computer)
https://www.lemon64.com/forum/viewtopic.php?t=78616&sid=4fa2e6a18af7cca9da4a9ca3f2fe4750
The real vintage 70s language labs had no computers but a big panel for the teacher and some few buttons and headset for every student. On most images on Google you mainly find the teacher’s panel, with the German term Sprachlabor you find some better ones.
Very interesting is this rather small but thick panel box for the C64
Some more images including rear
https://m.ebay-kleinanzeigen.de/s-anzeige/fuer-commodore-c64-schaltpult-aus-sprachlabor-/2012800215-225-2689