An apparatus and method for indicating operational characteristics of a machine, such as a motor vehicle or other type of human operator or monitored machine which is subject to variations in its operational characteristics requiring adjustments, maintenance or replacement of machine parts. In particular, the system and method involve the generation of synthetic speech signals which are converted to sounds of words and phrases or sentences which describe the operational characteristics of the machine and, in certain instances, suggest remedies or procedures to be taken by an operator or maintenance personnel to prevent machine malfunction, improve its operation and, in certain instances, optimize the manner in which it performs. Both analysis of the operational characteristics or ambient conditions to which the machine is subjected are effected by a plurality of sensors of such conditions and a computer or microelectronic processor which processes the outputs of the sensors and determines such operational characteristics, further controlling the operation of an electronic synthetic speech signal generator for generating speech signals which are converted to words, phrases and, in certain instances, sentences defining the operation and further defining suggested maintenance or variations in the operation to be taken by the operator thereof. Unsafe operating conditions may be electronically detected and immediately indicated or indicated at a future time when a memory is queriead.