1. A fast vocabulary independent method for spotting words in speech comprising the steps of: converting a speech waveform into a representation comprising phone-ngrams and a corresponding time interval of occurrence of each of the phone-ngrams; receiving phone-ngrams of at least one input word; performing a coarse match by selecting time intervals of the speech waveform having phone-ngrams that correspond to the phone-ngrams of the at least one input word; and performing a detailed acoustic match at the selected time intervals.
2. The method according to claim 1, wherein said step of converting the speech waveform comprises the steps of: generating feature vectors representative of the speech waveform; processing the feature vectors to generate the phone-ngrams for each word in the speech waveform; and storing the phone-ngrams and their corresponding time intervals in a look-up table.