Unsupervised data-driven pronunciation modeling

• US 20070067173A1
• Filed: 11/21/2006
• Published: 03/22/2007
• Est. Priority Date: 09/13/2002
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bellegarda, Jerome
• Granted Patent: US 7,702,509 B2
• Time in Patent Office: Days
• US Class Current: 704/260
• CPC Class Codes: G10L 15/063 Training
• CPC Class Codes: G10L 15/187 Phonemic context, e.g. pronunciation rules, phonotactical constraints or phoneme n-grams

Abstract

Pronunciation for an input word is modeled by generating a set of candidate phoneme strings having pronunciations close to the input word in an orthographic space. Phoneme sub-strings in the set are selected as the pronunciation. In one aspect, a first closeness measure between phoneme strings for words chosen from a dictionary and contexts within the input word is used to determine the candidate phoneme strings. The words are chosen from the dictionary based on a second closeness measure between a representation of the input word in the orthographic space and orthographic anchors corresponding to the words in the dictionary. In another aspect, the phoneme sub-strings are selected by aligning the candidate phoneme strings on common phoneme sub-strings to produce an occurrence count, which is used to choose the phoneme sub-strings for the pronunciation.

Claims

1. A computerized method comprising:

receiving pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

reproducing the pronunciation data for the out-of-vocabulary word as an audible signal.

2. The computerized method of claim 1 further comprising:

storing the pronunciation data for subsequent reproduction.

3. The computerized method of claim 1, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors corresponding to in-vocabulary words.

4. The computerized method of claim 3, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

5. The computerized method of claim 4, wherein the feature vector {tilde over ( v)}_p for the out-of-vocabulary word {tilde over (w)}_p is calculated as

{tilde over ( v)}_{p={tilde over (v)}p}S={tilde over (w)}_P^TU

where, S is a singular diagonal matrix, U is a left singular matrix, {tilde over (v)}_p is a vector within a right singular matrix V^T corresponding to the out-of-vocabulary word, and ^T denotes matrix transposition.

6. The computerized method of claim 1, wherein the dictionary comprises phoneme strings for in-vocabulary words.

7. A computerized method comprising:

receiving an orthographical space comprising a representation of an out-of-vocabulary word and orthographic anchors for in-vocabulary words, the orthographic space defined by a dictionary;

selecting phoneme sub-strings from the dictionary according to a closeness measure between the representation of the out-of-vocabulary word and the orthographic anchors for the in-vocabulary words; and

generating a pronunciation data for the out-of-vocabulary word from the selected phoneme sub-strings.

8. The computerized method of claim 7, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

9. The computerized method of claim 8, wherein the feature vector {tilde over ( v)}_p for the out-of-vocabulary word {tilde over (w)}_p is calculated as

{tilde over ( v)}_p={tilde over (v)}_pS={tilde over (w)}_p^TU

where, S is a singular diagonal matrix, U is a left singular matrix, {tilde over (v)}_p is a vector within a right singular matrix V^T corresponding to the out-of-vocabulary word, and ^T denotes matrix transposition.

10. The computerized method of claim 7, wherein selecting phoneme sub-strings comprises:

forming an orthographic neighborhood from in-vocabulary words corresponding to orthographic anchors that satisfy the closeness measure; and

creating a pronunciation data neighborhood from phoneme strings for the in-vocabulary words in the orthographic neighborhood, the phoneme strings having at least one phoneme sub-string in the dictionary.

11. The computerized method of claim 10, wherein selecting phoneme sub-strings further comprises:

selecting phoneme strings in the pronunciation data neighborhood for each context within the out-of-vocabulary word;

aligning the selected phoneme strings on common phoneme sub-strings; and

selecting a phoneme sub-string for each context from the common phoneme sub-strings.

12. The computerized method of claim 11 further comprising:

merging the phoneme sub-strings for adjacent contexts when two phoneme sub-strings overlap.

13. The computerized method of claim 11, wherein aligning the phoneme strings comprises:

calculating a minimum cost alignment A(k, l) between two phoneme strings φ

₁ . . . φ

_k . . . φ

_K and ψ

₁ . . . ψ

_l . . . ψ

_L having a length K and L respectively.

14. The computerized method of claim 13, wherein the minimum cost alignment is calculated as

A(k, l)=min{A(k−

1, l−

1)+C(k, l), G(i, k), H(j, l)}

where C(k, l) is the cost of substituting phoneme ψ

_l for phoneme φ

_k, (i, k) is the cost of a gap φ

_i . . . φ

_k, h (j, l) is the cost of a gap ψ

_j . . . ψ

_l,

15. The computerized method of claim 7, wherein the closeness measure comprises the cosine of the angle between the representation of the out-of-vocabulary word and an orthographic anchor.

16. The computerized method of claim 15, wherein the cosine K between the representation of the out-of-vocabulary word {tilde over ( v)}_p and an orthographic anchor v_j is calculated using

17. A computerized method comprising:

storing pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

transmitting the pronunciation data for the out-of-vocabulary word as an audible signal.

18. The computerized method of claim 17, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors corresponding to in-vocabulary words.

19. The computerized method of claim 18, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

20. The computerized method of claim 17, wherein the dictionary comprises phoneme strings for in-vocabulary words.

21. A computer-readable medium containing computer-executable instructions which, when executed, cause a processing system to perform a method comprising:

receiving pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings have pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

reproducing the pronunciation data for the out-of-vocabulary word as an audible signal.

22. The computer-readable medium of claim 21, wherein the method further comprises:

storing the pronunciation data for subsequent reproduction.

23. The computer-readable medium of claim 21, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors correspond to in-vocabulary words.

24. The computer-readable medium of claim 23, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

25. The computer-readable medium of claim 21, wherein the dictionary comprises phoneme strings for in-vocabulary words.

26. A computer-readable medium containing computer-executable instructions comprising:

an instruction to receive pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings have pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

an instruction to reproduce the pronunciation data for the out-of-vocabulary word as an audible signal.

27. The computer-readable medium of claim 26 further comprising:

an instruction to store the pronunciation data for subsequent reproduction.

28. The computer-readable medium of claim 26, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors correspond to in-vocabulary words.

29. The computer-readable medium of claim 28, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

30. The computer-readable medium of claim 26, wherein the dictionary comprises phoneme strings for in-vocabulary words.

31. A computer-readable medium containing computer-executable instructions which, when executed, cause a processing system to perform a method comprising:

receiving an orthographical space comprising a representation of an out-of-vocabulary word and orthographic anchors for in-vocabulary words, the orthographic space defined by a dictionary;

selecting phoneme sub-strings from the dictionary accord to a closeness measure between the representation of the out-of-vocabulary word and the orthographic anchors for the in-vocabulary words; and

generating pronunciation data for the out-of-vocabulary word from the selected phoneme sub-strings.

32. The computer-readable medium of claim 31, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

33. The computer-readable medium of claim 31, wherein selecting phoneme sub-strings comprises:

forming an orthographic neighborhood from in-vocabulary words correspond to orthographic anchors that satisfy the closeness measure; and

creating a pronunciation data neighborhood from phoneme strings for the in-vocabulary words in the orthographic neighborhood, the phoneme strings have at least one phoneme sub-string in the dictionary.

34. The computer-readable medium of claim 33, wherein selecting phoneme sub-strings comprises:

selecting phoneme strings in the pronunciation data neighborhood for each context within the out-of-vocabulary word;

aligning the selected phoneme strings on common phoneme sub-strings; and

selecting a phoneme sub-string for each context from the common phoneme sub-strings.

35. The computer-readable medium of claim 34, wherein the method further comprises:

merging the phoneme sub-strings for adjacent contexts when two phoneme sub-strings overlap.

36. A computer-readable medium containing computer-executable instructions comprising:

an instruction to receive an orthographical space comprising a representation of an out-of-vocabulary word and orthographic anchors for in-vocabulary words, the orthographic space defined by a dictionary;

an instruction to select phoneme sub-strings from the dictionary accord to a closeness measure between the representation of the out-of-vocabulary word and the orthographic anchors for the in-vocabulary words; and

an instruction to generate a pronunciation data for the out-of-vocabulary word from the selected phoneme sub-strings.

37. The computer-readable medium of claim 36, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

38. The computer-readable medium of claim 36, wherein the instruction to select phoneme sub-strings comprises:

an instruction to form an orthographic neighborhood from in-vocabulary words correspond to orthographic anchors that satisfy the closeness measure; and

an instruction to create a pronunciation data neighborhood from phoneme strings for the in-vocabulary words in the orthographic neighborhood, the phoneme strings have at least one phoneme sub-string in the dictionary.

39. The computer-readable medium of claim 38, wherein the instruction to select phoneme sub-strings further comprises:

an instruction to select phoneme strings in the pronunciation data neighborhood for each context within the out-of-vocabulary word;

an instruction to align the selected phoneme strings on common phoneme sub-strings; and

an instruction to select a phoneme sub-string for each context from the common phoneme sub-strings.

40. The computer-readable medium of claim 39 further comprising:

an instructions to merge the phoneme sub-strings for adjacent contexts when two phoneme sub-strings overlap.

41. A computer-readable medium containing computer-executable instructions which, when executed, cause a data processing system to perform a method comprising:

storing pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

transmitting the pronunciation data for the out-of-vocabulary word as an audible signal.

42. The computer-readable medium of claim 41, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors corresponding to in-vocabulary words.

43. The computer-readable medium of claim 42, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

44. The computer-readable medium of claim 41, wherein the dictionary comprises phoneme strings for in-vocabulary words.

45. A computer-readable medium containing computer-executable instructions comprising:

an instruction to store pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

an instruction to transmit the pronunciation data for the out-of-vocabulary word as an audible signal.

46. The computer-readable medium of claim 45, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors corresponding to in-vocabulary words.

47. The computer-readable medium of claim 46, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

48. The computer-readable medium of claim 45, wherein the dictionary comprises phoneme strings for in-vocabulary words.

49. An apparatus comprising:

means for receiving pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

means for reproducing the pronunciation data for the out-of-vocabulary word as an audible signal.

50. The apparatus of claim 49 further comprising:

means for storing the pronunciation data for subsequent reproduction.

51. The apparatus of claim 49, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors correspond to in-vocabulary words.

52. The apparatus of claim 51, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

53. The apparatus of claim 49, wherein the dictionary comprises phoneme strings for in-vocabulary words.

54. An apparatus comprising:

means for receiving an orthographical space comprising a representation of an out-of-vocabulary word and orthographic anchors for in-vocabulary words, the orthographic space defined by a dictionary;

means for selecting phoneme sub-strings from the dictionary according to a closeness measure between the representation of the out-of-vocabulary word and the orthographic anchors for the in-vocabulary words; and

means for generating a pronunciation data for the out-of-vocabulary word from the selected phoneme sub-strings.

55. The apparatus of claim 54, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

56. The apparatus of claim 54, wherein the means for selecting phoneme sub-strings comprises:

means for forming an orthographic neighborhood from in-vocabulary words corresponding to orthographic anchors that satisfy the closeness measure; and

means for creating a pronunciation data neighborhood from phoneme strings for the in-vocabulary words in the orthographic neighborhood, the phoneme strings having at least one phoneme sub-string in the dictionary.

57. The apparatus of claim 56, wherein the means for selecting phoneme sub-strings further comprises:

means for selecting phoneme strings in the pronunciation data neighborhood for each context within the out-of-vocabulary word;

means for aligning the selected phoneme strings on common phoneme sub-strings; and

means for selecting a phoneme sub-string for each context from the common phoneme sub-strings.

58. The apparatus of claim 57 further comprising:

means for merging the phoneme sub-strings for adjacent contexts when two phoneme sub-strings overlap.

59. An apparatus comprising:

means for storing pronunciation data for an out-of-vocabulary word, the pronunciation data comprising phoneme sub-strings selected from candidate phoneme strings having pronunciation data close to the out-of-vocabulary word in an orthographical space defined by a dictionary; and

means for transmitting the pronunciation data for the out-of-vocabulary word as an audible signal.

60. The apparatus of claim 59, wherein the orthographic space comprises a representation of the out-of-vocabulary word and orthographic anchors corresponding to in-vocabulary words.

61. The apparatus of claim 60, wherein the representation of the out-of-vocabulary word and the orthographic anchors are feature vectors.

62. The apparatus of claim 59, wherein the dictionary comprises phoneme strings for in-vocabulary words.