While many Cubans speak some (or even a lot!) of English, you should remember that you're visiting a Spanish-speaking country, so brushing up on some basic phrases isn't just helpful, but shows appreciation and respect for the culture. You can expect to find things like menus, road and store signage, reading materials, and more in Spanish as well, so it's smart to practice your skills in preparation for your travels.
Image Source: POPSUGAR Photography / Hilary White