Sacrosanctum Concilium §119

¹¹⁹ In certain parts of the world, especially mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life. For this reason due importance is to be attached to their music, and a suitable place is to be given to it, not only in forming their attitude toward religion, but also in adapting worship to their native genius, as indicated in Art. 39 and 40. Therefore, when missionaries are being given training in music, every effort should be made to see that they become competent in promoting the traditional music of these peoples, both in schools and in sacred services, as far as may be practicable.