If you only take one Spanish phrase book or dictionary with you on the Camino this is it Compiled by Sylvia Nilsen, an experienced Camino pilgrim, and her Spanish teacher, Reinette Novoa, the Lightfoot Guide Camino Lingo, English - Spanish Words and Phrases for Pilgrims on el Camino de Santiago contains all the Spanish words you'll need to walk a pilgrimage in Spain.
No complicated verb conjugations or rules on diphthongs and grammar.
This is a 'cheats' guide to speaking Spanish on the Camin.