PURPOSE: A method for increasing tenacity about the change of voice recognition apparatus environment for context subordination is provided to reduce observation distributions about a hidden mark model by maintaining memory usage rates and by effectively calculating a memory. CONSTITUTION: A training database(120) stores sounds in order to execute a voice recognition training. A dictionary(130) stores plural words in which are supported by a context subordinate type voice recognition unit. A voice recognition unit training module(150) trains one or more hidden mark models through the dictionary and the training data base. The voice recognition training module performs a non-uniform state clustering process about the state of each hidden mark model.
Improving the robustness to environmental changes of a context dependent speech recognizer