Whoa or Woah?
C.B. from Malibu, California, wrote, "How do we stop people from spelling 'whoa' as 'woah'? Please tell me when this misspelling started. Even professional websites misspell it."
Here's a way to remember the proper spelling: Who and ho are two origins that are often cited for whoa. For example, Dictionary.com states that ho came first as a Middle English command to make a horse stop and then evolved sometime around 1620 into whoa. To remember how to spell whoa, remember that the original word—ho, something you'd say to a horse—stays intact in the middle.
Also, in 1616 in the play "The Winter's Tale," William Shakespeare had a character known only as Shepherd call out "Whoa-ho-hoa!" Say it in your mind: whoa-ho-hoa. Say it loudly like Santa Claus: whoa-ho-hoa! The extra hos after the whoa should also help you remember to keep the ho in the middle.
2/27/2018: Here's a fascinating follow-up: "Woah" is more common and accepted in Britain than it is in the US, according to Lynne Murphy's research on the Separated by a Common Language blog.
Image courtesy of Shutterstock.