My daughter has all of a sudden developed a lisp when talking

My 5-year-old daughter has suddenly (in the last 3 weeks or so) developed a lisp when talking. When she says a word with the letter s, she puts her tongue in between her teeth. I have been correcting her and making her resay the word correctly. I had a lisp when I was little and had to go to speech therapy (at my public school) to get rid of it (and for trouble with my r’s and w’s).

I have no idea why she has started doing this. Has this happened to anyone else?