R is a programming language popular with statisticians. The language itself looks a bit like math and includes integration with SPSS and has many packages for data visualization and for working with text mining. One disadvantage is that R relies on your data being on your computer and also relies on your computer processing power, so it processes more slowly than some alternatives.
RStudio is a popular interface for R and includes the console for inputting commands, a window for viewing visualizations, and documentation for installed packages, as well as user prompts.
The first book introduces some basics for how to use R, including how to install additional packages. The other two books are specific to text mining. The second book offers many exercises where you can copy and paste the code to follow along.