The Italian alphabet, unlike the English one, counts only 21 letters. Officially K, J, W, X and Y are not part of the Italian alphabet. However, Italians can recognize these letters as they commonly appear in words that have been adopted as part of the Italian language. For instance the word yogurt is commonly used in Italian language too, and has no direct translation.
Another example is the water closet that in Italian language is spelled like in English as WC, however it is pronounced “viccì” (sounds like veet-chee) because the letter W in Italian language is often pronounced as V, not as U. In fact another way to refer to the WC is to call it “Water”, but pronounced it as “Vater”. Similarly the name Walter is pronounced as Valter. A fun fact is that Darth Wader from Star Wars has been renamed Lord Fener in the Italian version, because of the unique way Italians pronounce the letter W. In fact, Darth Wader would have sounded too close to the pronunciation of WC, making the character not as scary as he was supposed to be.
The word Xylophone is translated in Italian language as Xilofono, with the X being pronounced as a strong “ks”. So, strangely enough, although X is not in the Italian alphabet, there are indeed words containing the letter X. In Sardinia there is also a town containing a letter X, Arbatax.
Words like Joker have also become part of the common language, although when playing popular card games, other words such as “Matta” or “Pinella” are used to describe a Joker card. Yet Jack and King remain the same, with the letters J and K being used commonly.