Pig Latin is the most popular language game in the English speaking world.
Pig Latin is spoken by taking all consonants up to the first vowel, moving them to the end, and adding 'ay', or simply adding 'way' if the word starts with a vowel. For example, 'dog' becomes 'ogday', 'train' becomes 'aintray', and 'apple' becomes 'appleway'.
If the word starts with 'qu' or 'squ', move that to the end and add 'ay', instead of just moving the 'q' or 'sq'. So 'queen' becomes 'eenquay', and 'square' becomes 'aresquay'.
Since 'y' is a sometimes vowel, you sometimes have to determine whether it is a consonant or a vowel, and then translate the word accordingly. 'Yellow' becomes 'ellowyay', while 'style' becomes 'ylestay'.