Stuttering is more of a mental thing unless you developed it through drug abuse or a traumatic brain injury. The only way to stop stuttering is to not let yourself hear yourself stuttering.
I highly recommend this book
Stuttering & Anxiety Self-Cures: What 1000+ Stutterers Taught Me https://www.amazon.com/dp/1545478015/ref=cm_sw_r_cp_api_glt_fabc_C3K5A4D3R4GWSDK6ZH47