RiTa - an easy-to-use toolkit for experiments in natural language and generative literature. It includes text-generation via CFGs and Markov chains; taggers for syllables, phonemes, stress, POS. Rita also provides a Java-API for WordNet and morphology modules.
RNNLM Toolkit Tomas Mikolov - neural network based language models.
SimpleNLG - Java API for Natural Language Generation.
The Word Vector Tool - The Word Vector Tool is a flexible Java library for statistical language modelling. It especially supports the creation of word vector representations of text documents in the vector space model (each document is represented by the terms it contains). The vector space model is the point of departure for many text processing applications (e.g. web mining, text classification or information retrieval).