Apache OpenNLP is a free, open source toolkit for processing natural language text, based on machine learning. It includes common natural language processing functions such as tokenization, sentence segmentation, part-of-speech tagging, named entity extraction, chunking, parsing, and coreference resolution.

Processing is a free, open source programming language and development library for the visual arts. It is a software sketchbook, a way to visually learn programming fundamentals, and a tool for creating finished professional work, including mapping networks, textual analysis and producing visualizations. It runs under Windows, OSX and Linux environments, and can export graphics and applets in a variety of formats.

Many Eyes is a free collection of data visualization tools enabling exploration and discussion of the data. Users who post comments on a visualization may also save their view for others to see in conjunction with their comment. Visualizations can be created from the data sets loaded into the site, or one can upload a new dataset for use. Note: Uploaded datasets are shared with the site.

Philologic is a free, open source full-text search, retrieval and analysis tool developed by the ARTFL Project and the Digital Library Development Centre, at the University of Chicago. This tool supports a wide variety of XML and SGML encoded documents, in addition to plain text, Dublin Core and HTML, and includes a MySQL back end. It is designed ot be light, fast and robust, boasts extensive use and testing, and can be used directly 'out of the box' with numerous configuration options built in.

Tesseract is a free raw OCR engine originally developed by HP Labs and now maintained by Google. It works with the Leptonica Image Processing Library, and is capable of reading a variety of image formats. It can convert images to text in over 40 languages.

TUSTEP (Tubingen System of Text Processing Tools) is a free, open source, widely-used toolbox for text processing. It is aimed at scholarly audiences, can work with texts in both latin and non-latin scripts, and is primarily designed for humanites applications. Its modules include data capture, information retrieval, text collation, text analysis, sorting and ordering, rule-based textual manipulation, data export and typesetting. The user manual is only available in German at this time. This tool has been in continuous development since the 1960s.

INTEX is a linguistic development environment active until 2005. It includes large-coverage dictionaries and grammers, can parse texts of several million words in real-time, and tools to create and maintain large-coverage lexical resources, morphological and syntactic grammars, build lemmatized concordances and indices of large texts and identified semantic units.

GATE (General Architecture for Text Engineering) is free, open source software offered by the University of Sheffield since 1995. It provides a framework for users to gather a corpus, apply an ontology to it, develop markup, automate the application of the markup to the corpus and add tools such as knowledge facet search, ontology browsing or graphing.

FRANTEXT is a historically and culturally important database of French literary, philosophical and technical texts with an emphasis on diversity and representation, spanning the Middle Ages to the present, and offered on a subscription basis. This resource is aimed at linguists and literary scholars in the humanities and social sciences, and is notable for its inclusion of a powerful search engine called Stella. Stella is a sophisticated NLP search suite, and includes regular expression search, lemmatization, vocabulary list and entity categorization functions.

R is an open source programing language designed for statistical analysis and parallel computing. R began its life as a research project at the University of Aukland, but has since expanded to become a collaborativly run open source project run by the GNU. R has libraries for data import, regular expression data splitting, and visualization of data. R can be run as either a script or as a working environment.