How much spit does your mouth make in a single day?
Without thinking about it, you make close to a bottle of water in saliva every single day.
Your three major pairs of salivary glands produce roughly 0.5 to 1.5 liters of saliva a day - about a liter on a normal day. They drip steadily to keep your mouth wet and surge when you chew, smell, or taste food.
That 500ml bottle of water on your desk? Your mouth quietly makes one to three of those in saliva by bedtime, and you swallow nearly all of it without noticing.
Saliva output is far bigger than it feels - around a liter a day, swallowed silently.
That fluid starts digesting your food, protects your teeth, and keeps your mouth comfortable, which is why a dry mouth feels so bad.
One water bottle a day, dripping where you never see it.
Learn the idea and practice English at the same time.