Hello, Yes diabetes can definitely cause dry mouth and tongue but there can be various other causes which can result in such symptoms and they must be investigated to arrive at the diagnosis. Other most common causes can be... If you are a mouth breather If you are dehydrated because of fever,exercises,vomiting or diarrhea,extreme sweating etc. Since you are a hypertensive and if you are taking Diuretic,then it can result in dry mouth. Many other medications like anti histaminics or anti depression medicines can cause dry mouth Medical conditions like diabetes,anemia,hypertension,sjogren s syndrome etc can cause dry mouth Smoking and chewing tobacco can cause it It would be better for you to consult a doctor and get yourself investigated to find the exact cause. A proper treatment can be instituted,once the cause is found. Thanks