An apparatus for detecting an impairment state of a driver in a vehicle is provided. The apparatus comprises a vehicle interface device configured to receive a first audible signal from a driver indicative of at least one word while the driver is in a non-impaired state and to determine a first total time to recite the at least the word based on the first audible signal. The vehicle interface device is further configured to command the driver to recite the at least one word to determine the impairment state of the driver and to receive a second audible signal from the driver indicative of the at least one word. The vehicle interface device is further configured to determine a second total time to recite the at least one word based on the second audible signal and to compare the first total time to the second total time.