In admin/middleware.py:

from django.utils import translation


class AdminUsesEnglishMiddleware:
    """
    Force English to be used within admin section
    """

    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        if request.path.startswith('/admin/'):
            with translation.override('en'):
                return self.get_response(request)
        else:
            return self.get_response(request)

Then register the middleware in settings/__init__.py:

MIDDLEWARE = (
    .........<your other middleware>
    'admin.middleware.AdminUsesEnglishMiddleware',
)

What’s happening? We are running this middleware before every request where we check if the path matches our admin section’s path, and then temporarily changing the language with translation.override('en'), which is changed back to the previous language after the middleware runs.

Confirmed as working in Django 3.2, but should work in other versions of Django as well.