Speech Therapy is a training to help people with speech and language problems to speak more clearly. Not only a training but a treatment for speech and language disorders.
An oral development refers to the use and function of the lips, tongue, jaw, teeth and the hard and soft palates. Through speech therapy those refers to the use and function will be trained.
There are impacts of speech and language disorder to the child. First the self confidence will become lower, when the child cannot be easily understood, it is difficult to share ideas. Second the difficulty in reading/writing, child will apply his/her knowledge of speech and sounds when learning to read and write. Third the difficulty understanding/interpreting information, may make it feel like an important piece of the puzzle is missing, because he/she cannot understand you verbally.
So the goal of Speech therapy is simple enough-improved skills that will allow your child to communicate effectively.