Language popularity varies based on data sampled
RedMonk's analysis notably includes R, CoffeeScript and Assembly in its top twenty programming languages. These languages don't appear in the TIOBE top twenty, which instead lists several SQL variants, Pascal, Delphi, Lua, Ada and MATLAB – all languages that don't make RedMonk's list.
The TIOBE Community Index is based on finding the number of engineers working with a particular language from sites such as Wikipedia, Amazon, YouTube and several search engines. The RedMonk rankings are based on the programming languages prevalent for projects that share their code on GitHub and the number of interactions for a particular language on StackOverflow. Interestingly, the RedMonk analysts note that, in their observations, rankings didn't change much from month to month, while the TIOBE index does regularly show movement in this respect.