What is this weird coding I see in the description of the body of spam emails?

When I get spam emails lately and I read the description on my iPhone or run it through the Mozilla Thunderbird filter, the pictures turn into some random sequence of words, many of them often in Spanish.  For example, I got one of those obnoxious Heart attack defender spam emails, and I’m reading the description, and it says “anochecimos desembalariais deletrearíamos canijos volatilizaríamos trifasica comparaste formiban” and it goes on and on.  Some are just random words in both English and Spanish and often contain Unicode type symbols.  There should be a red flag raised for these, because they are obvious spam.  But the beat goes on and we just get inundated, even after creating dozens of filters.  Terrible experience.  If I didn’t have so many contacts attached, I’d just shut it down it’s THAT awful.