NLTK

I used this toolkit for my NLP project and although there were many features that did not work as i expected it to i found it really useful. The toolkit is written in python and python is a very easy and user-friendly language to learn.

Although, i knew a bit of python and used it extensively in the first semester for all the NLP assignments, i realised the actual utility and convenience of python w.r.t NLP tasks when i read the guide provided with the NLTK toolkit.

Although i am yet to use all the features provided in the NLTK , i have used the stemmers and different types of probability distributions.The learning curve for me was around a week including learning python part. Initially, i wondered if it really was worth all the effort as i could easily have implemented the algorithms in python or any other language.

The plus point was once i learnt how to use the toolkit, making enhancements took no longer than 5 minutes and in the end i could get quite a lot done.

The clean_html API of NLTK did not work. I either found the output contained the HTML tags or the text had disappeared! Further, since it uses the underlying HTML parser, its not resilient to malformed pages on the internet.

I found it easier to write my own code for implementing the Naive Bayes method. The NLTK provides many methods too. I would say its definitely been worth trying out the natural language toolkit and recommend it!

You can download NLTK at the following site:
http://nltk.sourceforge.net/