South America is not like Europe where people are expected to have some level of English ability. In the rural zones where you will probably spend much time traveling through, communication will be damn hard if you don’t know spanish.
I really think it’s a bad idea to go alone, even if you are a spanish master. Parts of south and central america are not all that safe, and much less safe for someone who doesn’t know the area and is a traveler. Rural america and rural latin america just don’t compare, rural latin america is much more poor and much more remote,