Welcome to the community! 1. We don't know exactly how the light works but essentially it's a paracausal power within the galaxy that can create countless things. The Light is also the name of an entity often referred to as the Gardner, but that's a story for another day 2. When a Ghost revives their Guardian for the first time they are bound to that Guardian and no one else. The bond between a Guardian and it's Ghost is the topic of much interest 3. The traveler doesn't choose it's speaker, rather every once and awhile a human is born that can "communicate" with the traveler through dreams and thoughts (and are often a magnet for random ghost's). I recommend reading the constellations lore book for further information 4. No actually, they're regular people however there's nothing preventing a Guardian from being a speaker 5. Technically? The light can do a lot of stuff, its essentially space magic that can do almost whatever you want it to 6. Yes, many. You can find one in the tower near Hawthorne