I know that colloquial French is quite different than standard French, which we are taught in school. I am not sure what exactly is different, though. Every time we learn a foreign language, we learn the more formal variety.
of course it's different- just like with english there are several different accents. also they speak much faster than your french teacher so its more difficult to understand.
A lot of letters and words are swallowed by the French people, which makes it quite hard to follow them. In addition to that the French generally speak very fast.
In school, we learn proper, perfect French. Think about proper, perfect English (Oxford English) and then think about how we actually talk to one another. Same thing in France.
