So the translation thing would solve the problem with site being displayed in another language, right?
About the permalinks:
Today I tried to publish a blogpost. At first both permalinks were displayed correctly (with the .com/de/postname vs. .com/en/postname1 thing correctly), after working on the title and actually publishing it, I found out that the permalinks are not working and they "magically" changed into .com/postname - and thus the link on the homepage did not work causing a redirect to the homepage.
The old correct permalink caused a 404.
So I re-published the blogposts creating a new blogpost, the permalinks were displayed correctly but did not work. Afterwards I changed them - making them from ".com/de/long-bun-haare-update" to ".com/de/long-bun-haar" which worked. Same for the english version - I just shortened them.
Could this be a valid hint for you?