The easiest to use web text analysis tool. Voyant is free and allows users to upload or paste text. The program determines word frequencies, colocates and display them graphically.
Creates a word cloud from your own text.
MALLET (MAchine Learning for LanguagE Toolkit) is a collection of tools that facilitate document classification, sequence tagging, and topic modeling. There is also an add-on toolkit (Graphical Models in MALLET) for visualization.
WordSeer is a collection of text analysis tools targeted at humanities scholars that includes side-by-side comparison, grammatical search, and document/sentence/word-set features.
Google Books Ngram Viewer FREE
Charts the frequencies of any word or short sentence using yearly count of n-grams found in the sources printed between 1500- present. If you are interested in performing a large scale analysis on the underlying data, download of the corpora is available
Google Books BYU View FREE
Compares The Corpus of Historical American English (COHA), Google Books (Standard), and the Google Books (BYU / Advanced) corpus in NGrams.
Cultoromics Bookworm Viewer FREE
Developed by Culturomics at Harvard, it is an interface tool for queries in the Google Books corpus. Users can run queries in highly selective corpora based on subject (books on world history, American books on science, etc.) though these corpora are much smaller than those in the full Google Books collection.
Data for Research is a free data mining tool for journal content on JSTOR, available to the public. It provides the ability to obtain data sets via bulk downloads, and includes a faceted search interface, online viewing of document-level data, downloadable datasets (including word frequencies, citations, key terms, and ngrams)