Patent Document ID: 9177558
Application ID: 13755790

Base Claim:
1. A computer-implemented method of assessing speech pronunciation, comprising: receiving speech for analysis via a computer-readable storage medium; performing automatic speech recognition on speech using a processor to generate word hypotheses for the speech, the word hypotheses identifying a set words recognized by an automated speech recognizer in the speech using one or more data processors; performing time alignment between the speech and the word hypotheses using the automatic speech recognizer to associate the word hypotheses with corresponding sounds of the speech; calculating statistics regarding individual words and phonemes of the word hypotheses using the processor based on said alignment; calculating a plurality of features for use in assessing pronunciation of the speech based on the statistics using the processor; and calculating an assessment score based on one or more of the calculated features.

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Claim 9:
9. The method of claim 1 , wherein the assessment score is based on one or more features selected from the group consisting of: an average likelihood across all letters: L 1 /m, where L 1 is a summation of likelihoods of all individual words: L 1 = ∑ i = 1 n ⁢ L ⁡ ( x i ) , where L(x i ) is a likelihood of word x i being spoken given an observed audio signal, where n is a number of words in a response, where m is a number of letters in the response; an average likelihood across all words: L 1 /n; an average likelihood per second normalized by a rate of speech: L 4 /R, where L 4 =L 1 /T, where T is the summation of a duration of all words in the response, where R=m/T s , where T s is a duration of the response; an average likelihood density across all words normalized by a rate of speech, L 5 /R, where L 5 ⁢ = ∑ i = 1 n ⁢ L ⁡ ( x i ) t i n , where t i is a duration of word i in a response; an average vowel duration shift: S _ = ∑ i = 1 N v ⁢ S v i N v , where N v is a total number of vowels, where S v i is the duration shift of vowel v i , which is measured as an absolute value of the difference between a duration of vowel v i and a standard value of a duration of a vowel estimated on native speech data, where S v i =|P v i −D v i |, where P v i is the duration of vowel v i and D v i is the standard average duration of vowel v i ; and an average normalized vowel duration shifts: S _ ⁢ n = ∑ i = 1 N v ⁢ Sn v i N v , where Sn v i is a normalized duration shift of vowel v i , which is measured as an absolute value of a normalized difference between a duration of vowel v i and a standard value of a duration of a vowel estimated on the native speech data, where Sn v i is calculated as  P v i P - D v i D  , where P v i is the duration of vowel v i , P is an average vowel duration across all vowels in the response being scored, D v i is a standard average duration of vowel v i , and D is a standard vowel duration estimated on all vowels in native speech data.