Creating Bag of words
create my custom bag of words with N-grams to apply to


My initial recommendation would be to use the NLTK library for Python. NLTK offers methods for easily extracting bigrams from text or ngrams of arbitrary length, as well as methods for analyzing the frequency distribution of those items. However, all of this requires a bit of programming.


  a functionality that can be achieved over GUI


That's tricky. Have you looked into GATE? I'm not exactly sure if/how GATE does what you want, but it does offer a GUI.