It’s interesting to note that psychological safety is NOT a natural thing: our instinct is to always try to protect ourselves by not speaking up. The reason is that the pros of speaking up are usually delayed and uncertain (something might go wrong if you speak up), while the cons are usually immediate and certain (your boss will certainly berate you for speaking up).
Therefore, you can’t expect people to speak up out of sheer willpower, because it’s unnatural. The trick to fostering psychological safety, then, is to completely flip the equation: