Speech Problem or Asthma

Patient: My son was diagnosed as having some speech disorder at birth and we were sent for therapy for him. As he grew, he started having problems with cough and cold which was diagnosed as Asthma. Please is it possible that it is the speech problem that is wrongly being diagnosed as Asthma? He has been on inhalers and the cough seems not to be reducing.What could we do to validate what is the main issue and work with a medical practitioner to resolve this?