Yes, you'll still be able to talk. I wore a protector myself for 15-ish years. Forgot it one day, naturally got shot just to the right of center my first game out. Solid throat shot. Second game, five seconds in, I got hit in exactly the same spot. I was more amused at taking two consecutive shots to the throat than I was in pain. I mean, what are the odds, really?
I wouldn't call a neck protector necessary in the same way I would classify goggles. Are they a good idea? Sure they are. Any protection you can wear is a good idea, just like knee pads, gloves, and groin protection. All those are optional, but when you really need them, not having them is going to hurt some.