Secret Cypher

My neighbor Amanda's home for Thanksgiving now and when she came over to visit tonight, we ended up solving a cryptogram. I told her that I once invented a code more complex than simple substitution. In fact, Chris Page and I invented a cypher in the 2nd or 3rd grade. Up until this point, very few people know much more than that. I've only shown the code to a handful of special people. However, I was just thinking "what's the point of having this code if there's nobody to use it with?"

So, here's the basic idea... You divide the alphabet up into vowels and consonants. Let me write them as sets:
V={a,e,i,o,u}
C={b,c,d,f,g,h,j,k,l,m,n,p,q,r,s,t,v,w,x,y,z}
When you have a word, the way you write it in the cypher is by replacing the actual consonant with the element of set C that comes before it in the set (b represents z). Likewise, the first vowel in every word is replaced by the element of the set V that comes before it (u represents a). No other vowels are changed.

Example:
Economics is fun.
Adomolibr er dom.

I know it's nothing fancy, but hey, what can you expect from a kid? This isn't useful for slipping things past the government or fooling a cryptologist, but it could be at least a little frustrating to someone who is trying to figure out your code with a simple substitution.