Speech impediments run in my family. My dad and brother both have mild speech issues but more like slurring and breathing problems. I have an honest to God stutter that manifested after I fell down a hill and hit my head on a tree when I was six. So I feel it's a combination of genetics and head trauma maybe. I definitely have ebbs and flows where I'll have days of pure fluency and then days of nothing but blocks. Have never really been able to pinpoint a cause - it seems random.