Case 1:

1. Go to Product Type.
2. Create new PT.
3. Go to Translation tab.
4. Remove English translation (the only one)

Result: 500 error which blocks /admin

Case 2:

1. Go to Attribute Groups.
2. Create new AG.
3. Go to Translation tab.
4. Remove English translation (the only one)

Result: 500 error which blocks /attribute-group list and attributes creation form.

Case 3:

1. Go to Attributes.
2. Create new attribute.
3. Go to Translation tab.
4. Remove English translation (the only one)

Result: Missing validation, all translations are removed.