French pronunciation:
* Marigot (as in the town in St. Martin): The emphasis is on the first syllable, and the "g" is silent. It sounds like "ma-ree-go".
English pronunciation:
* Marigot (as in a swamp or lagoon): The emphasis is on the second syllable, and the "g" is pronounced like the "g" in "get". It sounds like "mar-i-got".
So, the pronunciation depends on what you're referring to. If you're talking about the town in St. Martin, use the French pronunciation. If you're talking about a swamp or lagoon, use the English pronunciation.