Some Old Timers in New Mexico can still speak some of the medieval Spanish of their far distant immigrant ancestors, as leeneia probably can attest.
I have one cd of these old cantigas, but wouldn't attempt translation without knowledgeable help. Some have Galician influences, others are Asturian, Catalan, Euskari etc. (noted by Artbrooks, above).
The intricacies of Spanish medieval religion (Catholicism in Europe at that time not as uniform as it is today) will affect the translation as well. Far different from modern Spanish. (Just remember your struggles with Chaucer in school).
Some of the cds put out by Alia Vox have translations.