The reality is that this should address Spanish and an assortment of indigenous languages. For example, in San Antonio Palopó on Lake Atitlan, you are more likely to encounter someone speaking Kachiquel than Spanish.
My generic advice is learn the local language. While “point and grunt” will work in many situations if you actually want to become part of Guatemala, you should learn the local language. Everywhere I have been in Guatemala, Spanish is accepted as a perfectly OK language.
The good news is that if you are in a community where some Maya language is the most popular, Spanish spoken locally may be far from “good” Spanish. Thus, your bad Spanish is likely to be totally acceptable.
If you want to learn Spanish I highly recommend Duolingo (https://duolingo.com). It’s free and easy to invest a few minutes a day in learning a new language.