A special Byte Magazine article published for Byte's 20th anniversary special report
http://www.byte.com/art/9509/sec7/art19.htmTimeline chart, 1954 to today, printable; links to homes of many languages.
http://www.levenez.com/lang/Two diagrams showing how many languages are related to each other.
http://merd.sourceforge.net/pixel/language-study/diagram.htmlOriginal, historic first documents for many early programming languages, like language manualsa, scanned and converted to PDF form.
http://www.fh-jena.de/~kleine/history/Papers on use history of: comments, labels, literals, parentheses.
http://www.gavilan.edu/csis/languages/history.htmlA list of computer languages and some links to compilers for these languages.
http://www.scriptol.org/history.phpA poster plots over 50 programming languages on a multi-layered, color-coded timeline.
http://oreilly.com/news/languageposter_0504.htmlShort concise article on programming language history with some links.
http://www.princeton.edu/~ferguson/adw/programming_languages.shtmlHistory and critique of disagreements over language design details, citing some specific traits; by Brian Hayes. American Scientist.
2006.07.00This paper by Marat Boshernitsan includes an historical overview of some of the pioneering efforts in the field.
http://nitsan.org/~maratb/cs263/An encyclopedia description of PL/I history with many links to programming terms.
http://en.wikipedia.org/wiki/PL/I_programming_language