# US 2014/0195239 A1 · Systems and Methods for an Automated Pronunciation Assessment System for Similar Vowel Pairs

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- Number: US 2014/0195239 A1
- Document ID: US20140195239A1
- Status: Published application
- Kind: A1
- Application number: 14/148,772
- Filed: 2014-01-07
- Published: 2014-07-10
- Earliest claimed: 2013-01-07
- Assignees: Educational Testing Service
- Applicants: Educational Testing Service
- Inventors: Keelan Evanini
- Web page: https://patentgrep.com/patent/US20140195239A1

## CPC

- G09B 19/04: Speaking (with audible presentation of the material to be studied G09B5/04)
- G09B 5/06: with both visual and audible presentation of the material to be studied
- G10L 15/187: Phonemic context, e.g. pronunciation rules, phonotactical constraints or phoneme n-grams
- G10L 25/60: for measuring the quality of voice signals
- G10L 15/04: Segmentation; Word boundary detection
- G10L 25/15: the extracted parameters being formant information
- G09B: EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS (devices for psychotechnics or for testing reaction times A61B5/16; games, sports, amusements A63; projectors, projector screens G03B)
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

Computer-implemented systems and methods are provided for assessing non-native speech proficiency. a non-native speech sample is processed to identify a plurality of vowel sound boundaries in the non-native speech sample. Portions of the non-native speech sample are analyzed within the vowel sound boundaries to extract vowel characteristics associated with a first vowel sound and a second vowel sound represented in the non-native speech sample. The vowel characteristics are processed to identify a first vowel pronunciation metric for the first vowel sound and a second vowel pronunciation metric for the second vowel sound, and the first vowel pronunciation metric and the second vowel pronunciation metric are processed to determine whether the non-native speech sample exhibits a distinction in pronunciation of the first vowel sound and the second vowel sound.

## Claims

### Claim 1

A computer-implemented method of assessing non-native speech proficiency, comprising:
processing, using a processing system, a non-native speech sample to identify a plurality of vowel sound boundaries in the non-native speech sample;
analyzing, using the processing system, portions of the non-native speech sample within the vowel sound boundaries to extract vowel characteristics associated with a first vowel sound and a second vowel sound represented in the non-native speech sample;
processing, using the processing system, the vowel characteristics to identify a first vowel pronunciation metric for the first vowel sound and a second vowel pronunciation metric for the second vowel sound; and
processing the first vowel pronunciation metric and the second vowel pronunciation metric to determine whether the non-native speech sample exhibits a distinction in pronunciation of the first vowel sound and the second vowel sound.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first vowel sound and the second vowel sound form a set of phonetically similar vowel sounds.

### Claim 3 (depends on 2)

The method of claim 2, wherein a proficient native speaker pronounces the first vowel sound distinctly from the second vowel sound, and wherein a non-proficient non-native speaker pronounces the first vowel sound and the second vowel sound substantially identically.

### Claim 4 (depends on 2)

The method of claim 2, wherein the set of phonetically similar vowel sounds includes one or more of: /i/ versus /I/; /e/ versus /ε/; /a/ versus //; and /u/ versus //.

### Claim 5 (depends on 2)

The method of claim 2, wherein the set of phonetically similar vowel sounds includes one or more of: /i/ as in “cheese” versus /I/ as in “six”; /e/ as in “snake” versus /ε/ as in “chess”; /a/ as in “Bob” versus // as in “sun”; and /u/ as in “food” versus // as in “good.”

### Claim 6 (depends on 1)

The method of claim 1, wherein determining whether the non-native speech sample exhibits a distinction in pronunciation includes generating a vowel pronunciation score.

### Claim 7 (depends on 6)

The method of claim 6, wherein a score based on the vowel pronunciation score is automatically provided via a graphical user interface to provide feedback on non-native speech proficiency.

### Claim 8 (depends on 7)

The method of claim 7, wherein the feedback offers vowel pronunciation suggestions for improving communicative competence through better vowel pronunciation.

### Claim 9 (depends on 6)

The method of claim 6, wherein the vowel pronunciation score is used to generate a speaking proficiency score for the speech sample.

### Claim 10 (depends on 1)

The method of claim 1, wherein the vowel characteristics comprise vowel formant measurements.

### Claim 11 (depends on 10)

The method of claim 10, wherein a vowel formant measurement comprises a measurement of an amplitude peak in a vowel spectrum that indicates a resonant frequency of a vowel.

### Claim 12 (depends on 1)

The method of claim 1, wherein the first vowel pronunciation metric comprises an F2-F1 measurement, and wherein the second vowel pronunciation metric comprises an F2-F1 measurement.

### Claim 13 (depends on 12)

The method of claim 12, wherein the distinction determination is based on a calculation of:
Dist(vi, vj)=√{square root over (( F1vi− F1vj)2+( F2vi− F2vj)2)},
wherein F1vi is a mean F1 measurement for vowel i, wherein F1vj is a mean F1 measurement for vowel j, wherein F2vi is a mean F2 measurement for vowel i, wherein F2vj is a mean F2 measurement for vowel j.

### Claim 14 (depends on 1)

The method of claim 1, further comprising performing automatic speech recognition on the non-native speech sample to generate a transcript, wherein the transcript is used to identify the vowel sound boundaries.

### Claim 15 (depends on 1)

The method of claim 1, wherein a forced alignment procedure is used to identify the plurality of vowel sound boundaries.

### Claim 16 (depends on 1)

The method of claim 1, wherein a non-native speech proficiency score is based on the distinction determination and further based on a stress metric, an intonation metric, a vocabulary metric, or a grammar metric.

### Claim 17

A computer-implemented system for assessing non-native speech proficiency, comprising:
one or more data processors;
one or more computer-readable storage mediums encoded with instructions for commanding the one or more data processors to execute steps that include:
processing a non-native speech sample to identify a plurality of vowel sound boundaries in the non-native speech sample;
analyzing portions of the non-native speech sample within the vowel sound boundaries to extract vowel characteristics associated with a first vowel sound and a second vowel sound represented in the non-native speech sample;
processing the vowel characteristics to identify a first vowel pronunciation metric for the first vowel sound and a second vowel pronunciation metric for the second vowel sound; and
processing the first vowel pronunciation metric and the second vowel pronunciation metric to determine whether the non-native speech sample exhibits a distinction in pronunciation of the first vowel sound and the second vowel sound.

### Claim 18 (depends on 17)

The system of claim 17, wherein the first vowel sound and the second vowel sound form a set of phonetically similar vowel sounds.

### Claim 19 (depends on 18)

The system of claim 18, wherein a proficient native speaker pronounces the first vowel sound distinctly from the second vowel sound, and wherein a non-proficient non-native speaker pronounces the first vowel sound and the second vowel sound substantially identically.

### Claim 20 (depends on 17)

The system of claim 17, wherein the set of phonetically similar vowel sounds includes one or more of: /i/ versus /I/; /e/ versus /ε/; /a/ versus //; and /u/ versus //.

### Claim 21

A non-transitory computer-readable storage medium comprising instructions for which when executed cause a processing system to execute steps comprising:
processing a non-native speech sample to identify a plurality of vowel sound boundaries in the non-native speech sample;
analyzing portions of the non-native speech sample within the vowel sound boundaries to extract vowel characteristics associated with a first vowel sound and a second vowel sound represented in the non-native speech sample;
processing the vowel characteristics to identify a first vowel pronunciation metric for the first vowel sound and a second vowel pronunciation metric for the second vowel sound; and
processing the first vowel pronunciation metric and the second vowel pronunciation metric to determine whether the non-native speech sample exhibits a distinction in pronunciation of the first vowel sound and the second vowel sound.