9. The method of claim 1 , further comprising: providing the spoken confirmation of the identified semantic concept based on the semantic confidence level and an urgency level, the verbosity of the spoken confirmation decreasing with increasing urgency level.
1. A computer-implemented method of controlling a vehicle, comprising: receiving one or more instructions issued as speech; analyzing the speech using speech recognition software to provide a sequence of words and a word confidence measure for each word so recognized; analyzing the sequence of words to identify a semantic concept corresponding to an instruction based on the analysis, and a semantic confidence level for the identified semantic concept derived at least in part with reference to the word confidence measures of the words associated with the semantic concept; providing a spoken confirmation of the semantic concept so identified based on the semantic confidence level and an indicated verbosity level, the spoken confirmation being provided with one of a speaking rate or a pitch that is increased as the indicated verbosity level decreases; and using the semantic concept so identified to provide a control input for the vehicle; wherein the step of providing the spoken confirmation of the semantic concept comprises indicating that the instruction was not understood when the semantic confidence level is below a threshold, or the step of using the semantic concept comprises providing the control input for the vehicle when the semantic confidence level exceeds the threshold.