You may find Python more efficient for text corpus task. Here is a good beginning tutorial: http://www.pitt.edu/~naraehan/presentation/cmu_dh_workshop_2017.html
But I think you should consider sticking to the one you feel more comfortable.
I felt, working with Python is better. NLTK is a suite of libraries in python that provides many interfaces along with a feature called WordNet to find synonyms and antonyms as well. Please find the link below for more information.
FYI RStudio is the IDE, you mean R. In my opinion both are very similar. Nowadays, we see common libraries being built for both frameworks, and libraries that can run R-code in python and vice versa, especially in famous disciplines like NLP. If you are familiar with both, then you should go with the one you feel more comfortable with.
Let's try and simplify it then :). What is your background? If you come from a purely mathematical/statistical background then R will suit you better (remember, R was written by statisticians, not developers - Its greatest strength AND weakness). If you are coming from a more technical/programming background, then I 'd say python.