v1.7.1

v1.7.1 adds the ability to filter tweets on language. You can use from the command line, with one or more --lang arguments. So for example this will filter tweets that mention Paris or Madrid that are written in French or Spanish.

twarc filter paris,madrid --lang es --lang fr

You can also use programmatically:

for tweet in t.filter('paris,madrid', lang=['es', 'sp']):
    print(tweet['full_text'])

Thanks for the idea @tugrulz and for your patience!