Speech correlates of alcohol/drug impairment and its neurological basis is presented with suggestion for further research in impairment from poly drug/medicine/inhalent/chew use/abuse, and prediagnosis of many neuro- and endocrin-related disorders. Nerve cells all over the body detect chemical entry by smoking, injection, drinking, chewing, or skin absorption, and transmit neurosignals to their corresponding cerebral subsystems, which in turn affect speech centers-Broca’s and Wernick’s area, and motor cortex. For instance, gustatory cells in the mouth, cranial and spinal nerve cells in the skin, and cilia/olfactory neurons in the nose are the intake sensing nerve cells. Alcohol depression, and brain cell damage were detected from telephone speech using IMPAIRLYZER-TM, and the results of these studies were presented at 1996 ASA meeting in Indianapolis, and 2001 German Acoustical Society-DEGA conference in Hamburg, Germany respectively. Speech based chemical Impairment measure results were presented at the 2001 meeting of ASA in Chicago. New data on neurotolerance based chemical impairment for alcohol, drugs, and medicine shall be presented, and shown not to fully support NIDA-SAMSHA drug and alcohol threshold used in drug testing domain.