The languages that only puppies can understand.
PUPPY is an esoteric programming language that is made up of lowercase and uppercase forms of "BARK", "WOOF" and the spacebar.
One thing to note is that PUPPY only understands your code if it contains upper and lowercase forms of 'WOOF' and 'BARK'. If it contains something like 'WOO' or 'BAARK', the puppy will tell you that he doesn't understand your code. However, your code can contain something like 'BA rK' because the puppy removes the spaces before reading your code.
After you have mastered the rule above, PUPPY is extremely easy to learn. Like in Brainf_ck, you start off with a value set at 0, but only one. To add 1 to the value, you should type an uppercase letter and to take 1, type a lowercase letter. Ensure that you're following the above rule. To output the ASCII representation of the value, you use space.