CORRECTION: No one really thinks that eventually the CotCaught merger will spread to all of the US. There are some dialects where the vowels have drifted really far apart rather than merging together.

If you're curious how they sound unmerged, check this video out:    • Caught and Cot unmerged  

Next video, the one on Grimm's Law:
   • Grimm's Law  

Intro Song:    • Pink Clouds and Sticky Rain  
Outro Song:    • BlackGryph0n & Baasik  Quest (This C...