System and method for speech recognition modeling for mobile voice search

A system for generating an acoustic model for use in speech recognition, the system comprising:

• a processor;
• a first module configured to control the processor to receive training data;
• a second module configured to control the processor to identify non-contextual lexical-level features in the training data;
• a third module configured to control the processor to infer sentence-level features from the training data;
• a fourth module configured to control the processor to generate a set of decision trees by node-splitting based on the non-contextual lexical-level features and the sentence-level features;
• a fifth module configured to control the processor to decorrelate training vectors, based on the training data, for each decision tree in the set of decision trees to approximate full-covariance Gaussian models;
• and
• a sixth module configured to control the processor to train an acoustic model for use in speech recognition based on the training data, the set of decision trees, and the training vectors.

A non-transitory computer-readable storage medium storing instructions which, when executed by a computing device, cause the computing device to recognize speech, the instructions comprising:

• receiving speech;
• loading an acoustic model generated according to steps comprising:
• receiving training data;
• identifying non-contextual lexical-level features in the training data;
• inferring sentence-level features from the training data;
• generating a set of decision trees by node-splitting based on the non-contextual lexical-level features and the sentence-level features;
• decorrelating training vectors, based on the training data, for each decision tree in the set of decision trees to approximate full-covariance Gaussian models;
• and
• training the acoustic model for use in speech recognition based on the training data, the set of decision trees, and the training vectors;
• and
• recognizing the speech using the acoustic model.