First, that sucks! Sorry about your tumor. Glad it's both benign and removable. When is your surgery? Given that speech is a motor act and the cerebellum is involved in coordinating motor movements for speech production, a lesion to the cerebellum could impact speech. The people who stutter have demonstrated differences in the cerebellum related to speech production compared to people who do not stutter. That said, we don't know if those differences are cause or effect. The likelihood that your stuttering was caused by the tumor is impossible to know, however, stuttering is more often a developmental disorder rather than an disorder with an organic cause. So, the phrase "when I hear hoofbeats I think horses, not zebras" comes into play here. The more common thing is more likely than the surprising thing. If you stutter, and you've stuttered since childhood in all likelihood you have developmental stuttering and not a neurological stuttering caused by a cerebellar tumor. Best of luck with your recovery!