machine learning based toolkit for the processing of natural language text

 The Apache OpenNLP library is a machine learning based toolkit for the
 processing of natural language text. It supports the most common NLP tasks,
 such as tokenization, sentence segmentation, part-of-speech tagging, named
 entity extraction, chunking, parsing, and coreference resolution. These tasks
 are usually required to build more advanced text processing services. OpenNLP
 also included maximum entropy and perceptron based machine learning.