If you can read this article, you speak English and understand the language when it is spoken to you.
But what would happen if you had to travel back in time? How far back could you go and still be okay with our modern English? Like any other language, it evolves everyday and changes are considerable over generations.
This video by Yestervid explores the possibility that you would start having problems communicating with your modern day English if you travelled as far back as two centuries, and why.
This begs the question… Would you be interested in learning Old English?