Django-lettuce: where to keep language file
I do not know of lettuce, but I am guessing that you can include your file languages.py anywhere python can find it. 
I do this by appending the directory containing my files into sys.path. You could overwrite PYTHONPATH instead. A directory containing python code should have a __init__.py file. 
I am not sure if you already tried the above. If you did, you can ignore my answer.
I've added lettuce into my django project, where to keep the languages.py file in django project instead of modifying lettuce itself?
Sultan