On the page, the two languages’ vocabularies look similar. The heart is el corazón in Spanish and o coração in Portuguese. The infinitives of most common verbs are similar or identical. Yet in their spoken forms Spanish and Portuguese differ. Spanish is a rigorous, phonetic language whose letters are pronounced in the same way in every situation; Portuguese vowels, and even some consonants, are capricious, their sounds altering according to their position. Spanish has five vowel sounds; Portuguese, according to most linguists, has thirteen.