Starting off as a compiler I was writing, a few days later this branched out of it. MathLanguage is an incredibly cleverly named calculator-like thing that I wrote to aid in some calculations because I didn't want to spend the money to buy Mathematica. This was pretty much just thrown together for specific things that I needed it for, so the code can get messy and the UI maybe a bit unfriendly. Eventually I'll probably be making a second version that I will actually plan out and put effort into.
The repository and more information can be found here.