Here's why:
* Moon has a long "oo" sound.
* Juice also has a long "oo" sound.
* Joy has a short "oi" sound.
* Just has a short "u" sound.
Here's why:
* Moon has a long "oo" sound.
* Juice also has a long "oo" sound.
* Joy has a short "oi" sound.
* Just has a short "u" sound.