Patent Document ID: 8478597
Application ID: 11328651

Base Claim:
1. A computer-implemented method of assessing pronunciation difficulties of a non-native speaker, the method comprising: determining a plurality of different types of phonetic sources of pronunciation difficulties between a language of a non-native speaker and a second language, said determining including determining multiple types of sounds in the second language that cause pronunciation difficulties; assigning a weight to each phonetic source of pronunciation difficulty, the weight representing a measure of severity of the source of pronunciation difficulty; calculating using a processor a phonetic difficulty score, wherein calculating the phonetic difficulty score comprises calculating a product of a number of times the phonetic source occurs in an utterance of the non-native speaker and the weight of the phonetic source; calculating using the processor a language model score based on a sound comparison between the language of the non-native speaker and the second language, wherein the language model score is calculated based on a difference between a cross-entropy of the utterance with respect to a language model of the language of the non-native speaker and a cross-entropy of the utterance with respect to a language model of the second language; normalizing using the processor the phonetic difficulty score and the language model score; and calculating and outputting a metric from the normalized phonetic difficulty score and the normalized language model score, the metric providing an assessment of pronunciation difficulty.

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Claim 5:
5. The method of claim 1 , wherein normalizing the phonetic difficulty score and the language model score comprises determining a normalized phonetic difficulty score and a normalized language model score such that the mean of the normalized phonetic difficulty score is equal to the mean of the normalized language model score and the standard deviation of the normalized phonetic difficulty score is equal to the standard deviation of the normalized language model score.