DragonDictate was first released for DOS, and utilized hidden Markov models, a probabilistic method for temporal pattern recognition. At the time, the hardware was not powerful enough to address the problem of word segmentation, and DragonDictate was unable to determine the boundaries of words during continuous speech input. Users were forced to enunciate one word at a time, clearly separated by a small pause after each word. DragonDictate was based on a trigram model, and is known as a discrete utterance speech recognition engine.[7]