Patent US 5,774,851

An apparatus includes a speech pattern memory, a microphone, an utterance length detector circuit, an utterance length selector circuit, switches, and a pattern matching unit. The speech pattern memory stores a plurality of standard speech patterns grouped in units of utterance lengths. The utterance length detector circuit detects an utterance length of speech data input at the microphone. The utterance length selector circuit and the switches cooperate to read out standard speech patterns from a speech pattern memory corresponding to the utterance length detected by the utterance length detector circuit. The pattern matching unit sequentially compares the input speech pattern with the standard speech patterns sequentially read out in response to a selection signal from the utterance length selector circuit and performs speech recognition.