The CMU air travel information service
Wayne Ward · 1990
Understanding spontaneous speech presents several problems not found in processing read speech input. Spontaneous speech is often not fluent. It contains stutters, filled pauses, restarts, repeats, interjections, etc. Casual users do not know the lexicon and grammar used by the system. It is therefore very difficult for a speech understanding system to achieve good coverage of the lexicon and grammar that subjects might use.