Look at the camera. Ready? Say "cheese"!
Why do we say "cheese" when someone takes our photo? It is an old custom.
Long ago, people did not smile for photos. In the 1800s, cameras were new. Taking a photo took a long time. You had to sit very still. If you moved, the picture was blurry. Also, people thought smiling made them look silly. Rich people wanted to look serious in portraits. So, they kept a straight face.
By the 1930s and 1940s, cameras got better. Photos became fast and fun. People started to smile more.
Why "cheese"? Saying the word "cheese" forces your mouth into a wide smile. Try it. Say "cheeeee-se." Your lips stretch wide. Your teeth show. It looks like a happy grin.
Some other countries use different words for photos. In France, people say "ouistiti" (a small monkey). In Spain, they say "patata" (potato). In Italy, they say "diciotto" (eighteen). All these words make your mouth move into a smile shape.
Today, we take photos with phones every day. We say "cheese" at birthday parties, on trips, and with friends. It is a simple trick for a happy picture.
What do you say when someone takes your picture?