Abstract: An improved speech model and methods for estimating the model parameters, synthesizing speech from the parameters, and quantizing the parameters are disclosed. The improved speech model allows a time and frequency dependent mixture of quasi-periodic, noise-like, and pulse-like signals. For pulsed parameter estimation, an error criterion with reduced sensitivity to time shifts is used to reduce computation and improve performance. Pulsed parameter estimation performance is further improved using the estimated voiced strength parameter to reduce the weighting of frequency bands which are strongly voiced when estimating the pulsed parameters. The voiced, unvoiced, and pulsed strength parameters are quantized using a weighted vector quantization method using a novel error criterion for obtaining high quality quantization. The fundamental frequency and pulse position parameters are efficiently quantized based on the quantized strength parameters.

Abstract: A technique for teaching second language writing skills provides for analyzing a user text. The user text is analyzed and compared to a writing culture. The differences between the user text and the writing culture are identified. The identified differences are compared to linguistic flaw information previously compiled from other second language texts written by first language writers in the writing culture. Identified differences that are found in the linguistic flaw information store are used to retrieve contextually relevant corrections and comments for addressing the identified flaws based on the first and second language and writing culture.