Not so in Mexico. Certainly, many Mexicans know or at least understand English, especially those who work within the tourism industry as well as professionals in international government, business, and science, but for day-to-day living and interacting, one should learn Spanish. Yes, I wrote should not must. In fact, absent a few essentials (hello, good-by, please, thank you, where's the bathroom, etc.) one can survive without the language. But surviving is not really living.
Most people born and raised in northern Belize learn Spanish as their first language so it is quite commonly used here. This has given us exposure to the language and an opportunity to be conversant with the most common phrases and to attune our ears to the lilt and cadence of the language. But that is a far cry from being able to carry a conversation. So lately, we've applied ourselves to learning the language and it has proven interesting because Wifey and I are approaching it from two different backgrounds.
There are two easy jump-starts to learning Spanish and both involve cognates, or similar words. Firstly, many English words have Spanish roots such as abalone, alligator, mesa, ranch, etc. For a long list, check out this page on Wikipedia. Secondly, Spanish has hundreds of words that are similar to English, with the only difference being the Spanish words will end in a vowel. Musica, rápido, el chocolate, el taxi, etc. Here's a list you might find interesting and will surprise you with how much Spanish you already know.
I learned both English and French as a child. This set me up with a natural ability to learn other languages and I've dabbled, to a greater or lesser extent, in German and Italian and can get into into trouble (grins) using Tagalog, Malay, and Thai. Between my background and the cognates, I'm picking it up rather quickly though it's been said I speak Spanish with a somewhat European accent. My hiccups in learning and using the language come directly from my background.
As a small but, I think, interesting example, there are masculine and feminine nouns or objects in Spanish (as in French) unlike English where everything is neutral. Un hombre (masculine), una senorita (feminine). In Spanish, un (pronounced like "rune" without the "r") denotes something masculine. However, in French, the feminine (une) is pronounced the same way. So I'm somewhat challenged by the fact I'm saying, in Spanish, un hombre, when in my head it sounds like I'm using the French feminine "une". Perhaps you need to speak French to understand this but it is a bit of a stumbling block for me. It's not uncommon for me to use the French pronunciation of "un" (which sounds quite different for the masculine article) instead of the Spanish. As well, I'll slip in a French or Italian word in a Spanish conversation when I get on a run! But always those with whom I'm conversing take it in stride and all's well.
Wifey, however, has no language training beyond English. For her, learning Spanish is a big deal but she's excited, has dedicated herself to the task, and is making rapid progress. She is using a combination of computer courses, immersion (living in Mexico!), tutoring (her tutor, Wendy, in the picture above), and the help of a 3rd grade primer. In a rather short period of time she's already able to follow the general gist of conversations and feel comfortable with the normal day-to-day greetings and to travel and shop on her own. The important stuff, haha!
There are ample aids to learning a new language. Most everyone has heard of Rosetta Stone and it's OK but too slow for me. It teaches a lot of vocabulary and has a special capability of using your computer's microphone to hear you talk and evaluate your accent and inflection. It does work and many people find it an interesting way to learn. My favorite, though not Wifey's, is the Michel Thomas course that relies heavily on cognates and has you speaking useful sentences by the end of the first lesson.
Courses aside, there's no better way to learn than by immersion. Live where everyone is speaking Spanish and you'll quickly pick up the basics - same-same for any language. Another trick for those who have a hobby or passion in a particular subject, is to learn the vocabulary for that hobby. It's an interesting way to get a jump on things. Finally, no matter where you travel, any valiant attempt to converse in their native language is greatly appreciated and reaps ample rewards.
Hasta pronto amigos!