Is it 'further' or 'farther'?

Further and farther. They're one letter apart; how different could they be? Well, we regret to inform you that English is at it again. Also, let's get into another linguistic curiosity: how did we end up with the phrase "raining cats and dogs"?Hosted by Emily Brewster, Neil Serven, Ammon Shea, and Peter Sokolowski.Produced in collaboration with New England Public Media.Transcript available here.See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.