J is the tenth letter and was not originally in the English alphabet. It was originally the letter I but n the 16th century, the letter J was created. It was acquired directly from the French alphabet but adopted a different, harder sound.
The letter J has a dz sound and was originally noted as cg and cz. However, the I became popular and then afterwards the J was created. Words like jest were once known as iest. However, there are some words that sound like should be a J but are two consonants put together, such as dg. The first note of J being used was in 1634 but it did not become popular right away.
J can have a softer or even a silent sound. This is when the letter sounds more like a Y, such as words like Hallelujah.
While it is used popularly in the English language, it is not something that is popular in any of the modern Celtic languages. The Native Americans also hardly used the letter J.
There is just one J in a game of scrabble so you may not come across it that often. However, when you do, you will get 8 points. It is worth looking at using it carefully and trying to place it on one of the bonus tiles to get as many points as possible. If you get it at the start of the game, it is worth taking the time. However, if you are getting close to the end of the game, you will need to start thinking about just using it, because it is a lot of points to be left with.