7. The method of claim 5 , wherein the representations of the first-language speech sounds are indicative of Gaussian density functions (GDFs) that estimate one or more spectral features of the first-language speech sounds, wherein the representations of the second-language speech sounds are indicative of GDFs that estimate one or more spectral features of the second-language speech sounds, wherein determining the association probabilities in the third vector comprises identifying a given mean value of GDF in the first vector proximal to a given mean value of GDF in the second vector.
7. The method of claim 5 , wherein the representations of the first-language speech sounds are indicative of Gaussian density functions (GDFs) that estimate one or more spectral features of the first-language speech sounds, wherein the representations of the second-language speech sounds are indicative of GDFs that estimate one or more spectral features of the second-language speech sounds, wherein determining the association probabilities in the third vector comprises identifying a given mean value of GDF in the first vector proximal to a given mean value of GDF in the second vector. 8. The method of claim 7 , wherein determining the association probabilities in the third vector is further based on a phone mapping table or Viterbi decoding.