How do you know how to say words that have unusual spelling?
Nowadays you can just google “how to pronounce (the word)” and you will get an immediate answer. Your best source is a good dictionary, on or off line. There is a “key” that explains the system of sounds used (often it is the International Phonetic Alphabet). When you look up the word in question, refer back to the “key” in order to learn how to say it. The dictionary will also have a system to tell you which syllable(s) to emphasize.