sorry for this misunderstanding. I tested the "student" and the "teacher" account with the real old app on iOS and I found no problem. I deleted the accounts and I could log in. This first test should show if David's problem comes from the website.
Now I am logged in with https://prototype.moodle.net/mobile/webapp/ and this is Moodle Mobile 3.4.0 of course. I opened the web app with the Safari browser on macOS 10.13.1 and it looks fine! It seems to be a nice testing environment for the app.
I switched the language to german and I found that all notifications names are still in english. I hope you will get it with the following url https://prototype.moodle.net/mobile/webapp/#/site/mm_settings/notifications-preferences (screenshot 1).
Also some strings on the page https://prototype.moodle.net/mobile/webapp/#/site/mm_settings/messages-preferences are still in english.
On the page https://prototype.moodle.net/mobile/webapp/#/site/myoverview I clicked on the three points right for the course "Celebrating Cultures". The menu item "Competencies" is still in english (screenshot 2). Clicking on the item I get the page "Kurskompetenzen" ... okay, this is correctly the german translation for "Course competencies".
Then I switched to https://prototype.moodle.net/mobile/webapp/#/site/myoverview and looked at the timeline. The todo list on the right side is in english (screenshot 3).
Now I looked at die course grading https://prototype.moodle.net/mobile/webapp/#/site/coursesgrades/grades. I tied this for the course ""Celebrating Cultures" and found the english text "Course total. Simple weighted mean of grades." (screenshot 4) On this page you also see the english phase names "submission" and ""assessment". And there is the word "empty" which is not translated.
On a learning plan page https://prototype.moodle.net/mobile/webapp/#/site/learningplans/learningplan I found some more english words: "learning plans" (headline) and "competent" (green field). The other english words "active", "constructive", "communicative", "civic", "creative", "critical", "cognitive", "confident" and "cultural" are competencies of the learning plan ... I don't know if the competency names but be translated in AMOS or in die settings of the test moodle. (screenshot 5).
If I should write my results to a different website then please let mi know.
Best regards, Ralf