Spain Spanish vs. Latin American Spanish
Just like in English, different Spanish-speaking countries and regions have distinct accents when spoken. The main phonetic difference between Spanish in the Americas and Spain is that two sounds have been modified: the z sounds like s, and ll sounds like y. In countries like Bolivia and Peru, the z sound is lost, but ll is retained. In Argentina and Uruguay, both ch and ll have a characteristic hard sound. In Mexico, vowels are often reduced to a schwa (similar to the a in English words like about, celestial, gorilla). In Puerto Rico and Cuba, there is a tendency to mix up r and l. In many countries, the j sound is softer and pronounced more like the English h (as in hot). In Chile, for instance, you may hear people say mujier instead of mujer.
Despite these differences, two Spanish speakers from different regions will almost always understand each other, provided they use the cultivated or formal versions of their respective dialects. However, comprehension may be impaired if fast or colloquial speech is used.