I have a what is like a little sackbubble under my tongue what canit be .

Ranula/Mucocele: A ranula is a mucus filled cyst like structure near the minor salivary glands under the tongue. It occurs when mucus leaks into tissues surrounding the gland. A ranula may spontaneously resolve after a few months. Alternatively topical steroids may be used but the ranula may recur after stopping the medication. Surgery is an option if there is enlargement or recurrence.

Sialolithiasis: Most common is a blocked salivary gland,often with a calcification called a sialolithiasis or stone.It can often be loosened and ejected by placing a very small probe into the duct.If unsuccessful,then it can be surgically removed.Also,this can occur if the duct is injured, swollen or inadvertently sutured and thereby blocked. If this,then it will enlarge at mealtimes.See Oral Surgeon. Good Luck.

Harmless mucocele: Usually they're not a problem and will go away on their own. If concerned see your dentist for evaluation.

Possible Ranula: A ranula presents as a fluid filled bubble on the floor of the mouth under the tongue. It is caused by a blocked salivary gland. The saliva can't get out so it backs up and creates a bubble. Small ranulas can often resolve on their own. Larger ones (shown here) may require surgical removal.

Sack bubble: I agree with Dr Schneider that these bubbles under the tongue are often ranula. I generally treat with proteolytic enzymes such as papain / bromelain to reduce swelling -open the blocked duct. It is often safe to just leave them alone. I rarely need to remove these surgically, unless so large that they interfere with speech.

Blocked duct: Could be a ranula or blocked salivary duct. See oral surgeon for assessment/recommendations.