Acquired stuttering can be caused by some sort of brain injury, drug use (some psychopharmaceutical drugs have this side effect), sleep deprivation, intense stress… The specialists you are consulting will ask you for your medical history and for any changes in your circumstances. The good news is that acquired stuttering is treatable. One of my patients started stuttering in his 20s, most likely because he was on medication for his depression. His treatment was completely successful and 15 years later he is still stutter free. I hope the reason for your stutter is as benign and your treatment as successful.