In lessons 1-3, you learned how to identify cognates in languages, and how to use those cognates to compare languages to their family members. Now I show you how to reach back into the past in order to uncover and reconstruct an unattested parent language. The "Intro to Historical Linguistics" series is a remastered version of four older videos from nativlang.com. NOTE: links now obsolete. Instead see my playlist on "Sound change":    • Historical Sound Change   Visit the website for more information, including examples and exercises: http://www.nativlang.com/linguistics/historical-linguistics-lessons.php Here's my course on the International Phonetic Alphabet: http://www.nativlang.com/linguistics/ipa-pronunciation-lessons.php This page lists regular sound changes with examples of each type of sound change: http://www.nativlang.com/linguistics/historical-sound-changes.php music by Kevin MacLeod