Hi, 
Please advise on NLP libraries similar to Natural Language Toolkit (www.nltk.org
First of all I need:
- tools to construct 'bag of words' (http://en.wikipedia.org/wiki/Bag_of_words_model), which is a list of words in the
article.
- tools to prune common words, such as prepositions and conjunctions, as well as extremely rare words, such as the ones with typos. 
- stemming tools 
- Naive Bayes classifier 
- SVM classifier 
-  k-means clustering

Thanks!