Hi Jane,
Yes I know someone with what "sounds similar". I assume you have seen a specialist regarding this. Did you have a CT and MRI scan?
If this is now affecting your speech it too can start to produce other symptoms, something that can't go unattended as treatment option may be lessened.
This type can produce calcium deposits and depending where they are located give rise to the named type and symptoms.
(PNET) primitive neuroectodermal tumors - as this is in the cerebellum they call it medulloblastoma. Early stages they can operate along with chemotherapy.
Please understand a specialist is required in your case, I can only give you insight.

I hope this helps you but if you would like any more info glad to help.
Best wishes
Nick