What's the plural of "lingua franca"?
But if the term comes from Italian, does the plural in Italian would be "linguae francae", as Merriam-Webster says (http://www.merriam-webster.com/dictionar... ), as if it were Latin?
And to finish, how should the plural be in Spanish? ¿"Lenguas francas"? In Spanish I always use "lingua franca" and not "lengua franca". In that case, should I go with "linguae francae" or with the Spanish version?