Here's why:
* French pronunciation: In French, the "ou" sound in "moulin" is a long, open "oo" sound, similar to the "oo" in "moon".
* English pronunciation: When English speakers borrow French words, they often adapt the pronunciation to their own language rules. In this case, the "ou" sound in "Moulin" is often pronounced with a shorter, more closed "oo" sound, similar to the "oo" in "book".
So, although "moulin" should technically sound like "moo-lan", it is commonly pronounced as "moo-lin" in English.
This is a good example of how language can be borrowed and adapted over time!