Formal Language Theory

The Chomsky Hierarchy of Formal Grammars
A brief definition of the grammars which define the Chomsky hierarchy of families of languages.
http://www.spectrum.uni-bielefeld.de/Classes/Winter97/IntroCompPhon/compphon/node66.html

Formal Language Theory
An introductory approach to the topic using many examples.
http://everything2.com/index.pl?node_id=113762

Formal Language Theory
A lecture on grammars, generating languages from grammars, the Chomsky classification and derivation trees. [PDF]
http://www.inf.unibz.it/~artale/Compiler/slide2.pdf

Formal Language Theory for Natural Language Processing
A draft manuscript with chapters on set theory, regular languages, context free languages and the Chomsky hierarchy. [PDF]
http://www.helsinki.fi/esslli/courses/readers/K10.pdf

Graduate Programming Languages
Lecture notes from the University of San Francisco with examples from natural languages, parsing with YACC, the use of LL(k) grammars and the hierarchy of regular, LL(k), LR(k), context free, context sensitive and unrestricted grammars.
http://www.antlr.org/wiki/display/CS652/CS652+Home

Grammars
A set of slides on grammars and language generation, with examples including a grammar for an abbreviated C language.
http://www.cs.princeton.edu/courses/archive/fall2000/cs126/lectures/T3-4up.pdf#search=%22context%20sensitive%20languages%20compilers%22

Grammars and Parsing
Description of several types of formal grammars for natural language processing, parse trees, and a number of parsing methods.
http://www.cse.unsw.edu.au/~billw/cs9414/notes/notes.html

A Hierarchy of Languages
A brief discussion of context sensitive languages, recursively enumerable languages and languages with no grammars. Examples show these are not equivalent.
http://web.cecs.pdx.edu/~jhein/lectures/Section.14.2.pdf#search=%22context%20sensitive%20languages%22

Lecture Notes
Notes for a class at Virginia Tech covering formal languages and their connections with finite automata, pushdown automata and Turing machines.
http://courses.cs.vt.edu/~cs4114/lectures/index.html

LING 106 Introduction to Formal Linguistics
Lecture notes providing definitions, examples, theorems and problems. Course taught at University of Pennsylvania, Department of Linguistics.
http://www.ling.upenn.edu/courses/Fall_2006/ling106/Ling106.htm