MeierEce, generally base of tongue cancer victims don't present with any symptoms until it has metastastized to the regional lymph nodes. Then the symptom is a lymph node that has swelling that does not subside. This was my case.
When you see your ENT, you should expect a very thorough physical exam in that he's going to be feeling around the outside of your neck as well as all around the inside of your mouth. Chances are he's going to scope you, which includes running a small, flexible, lighted tube up your nose and down the back of your throat. From there he'll be able to inspect the base of your tongue, your lyrnax as well as other structures in your throat. If he finds the lumps in your mouth suspiscious, he may stick a needle in them and extract some cells for pathological review. This is called fine needle aspiration (FNA). Keep in mind that biopsy and pathological inspection is only concrete diagnostic method.
Best of luck...
-Brett