Does a dry mouth cause your tongue to feel tired when chewing and sore. i haven't ate a much, and it takes me longer to eat because it feels tired. ?

Saliva: It can. Saliva helps break down carbohydrate in food. If you are lacking saliva, it is like chewing a hand full of saltine crackers all at once. You can't break down the food very easily and instead of the chemicals (salivary enzymes) helping break down the food, you rely more on your tongue and teeth, which means more chewing and sore/tired muscles. At your age, go see a dentist for the cause.