People can't understand me when i speak. would speech therapy help?

Most likely, yes.: A Speech/Language Therapist will evaluate you, then discuss therapy & prognosis. Is your Articulation Disorder Developmental, from childhood, or from a Central Nervous System insult, Neuromuscular Disorder, Hearing Impairment or any other medical issue? If the onset was in adulthood, I trust you've seen your primary physician in order to find the etiology, or cause. (S)he can refer you to an SLT.