Sketch Engine blog provides a simple introduction to various topics relating to text corpora and their processing including illustrative examples.

Topic classification

Topics and genres in corpora

corpus attributes
corpus from the web
blog: pos tags

POS tags

OneClick Terms - multi-word term extraction

The best term extraction

Screenshot of thesaurus from esTenTen Spanish corpus

Automatic thesaurus

Screenshot of word sketch from enTenTen English corpus