My guess is that you would either be: a) speaking English with the Dutch, German, UK, Irish, Canadian (some), and US pilgrims; b) really bad Spanish with the Spanish pilgrims, few of whom would be giving you much information on the agreement of nouns and verbs, the preterite, or the distinction between ser and estar; and c) sign language and pantomime with the Italian, Portuguese, Polish, and Korean pilgrims. I would agree with those who suggest that you can't do both easily. Perhaps if you were on one of the quieter routes, where you don't have many pilgrims, and could arrange for lessons--- in one of the towns on the del Norte, perhaps?