Fwah, also spelled "F'wah," is a cosmic sound made by the Universe. Sort of like, "Om," but less dignified. It can also be used as a sort of enthusiastic greeting, usually immediately following the person's name. Also known as an emotion of impending disaster.
"This cosmic notion fills me with a great sense of fwah."
(common occurances of F'wah: telephones, random radio gibberish, and anything in the immediate vicinity of Roseanne Barr.)
Originally, "muh" was a contraction of "muwahahaha," a sort of quick way of adding diabolical laughter to a phrase. It now has a number of meanings, and is often used as a random interjection, or just dispersed throughout a sentence. At the end of a sentence, it adds an emphatic note to the whole. Standing alone as an adjective, it means something so bizarre or intrisically unique that it can't be described any other way. In front of an adjective or adverb, it acts as an intensifier. Muh is also associated with a pink paranoid chihuahua, although experts haven't yet determined just how this applies. Muh can also be used as a greeting, a challenge, a threat, or just something fun to scream at the top of your lungs (an act referred to as a "screamuh").
"Now, I will destroy the space station with my positronic ray! MUH!"
"That woman has muh hair."
"This was the most muh delicious dessert I've ever eaten."