Abstract: A method for automatically generating a pronunciation dictionary in a speech recognition system is disclosed. Pronunciation patterns of a large scale pronunciation dictionary are learned through a neural network without resorting to a phonetic knowledge, and the pronunciation sequences for input words are accurately formed by utilizing an exception grapheme pronunciation dictionary, an exception word pronunciation dictionary for graphemes and words prohibiting the formation of an accurate pronunciation dictionary through the learning neural network, thereby reducing the size of the memory and the amount of calculations. A multi-layer perceptron for directly mapping phonemes relevant to respective graphemes is taught by utilizing a neural network, so as to form an exception word pronunciation dictionary data base, an exception grapheme pronunciation dictionary data base, and a phoneme output multi-layer perceptron parameter data base for respective graphemes.