7. A non-transitory computer readable medium having stored therein instructions, that when executed by a computing device, cause the computing device to perform functions comprising: receiving a speech signal; determining acoustic feature parameters for the speech signal, wherein the acoustic feature parameters include phase data, wherein determining the phase data involves using a relative phase shift model; based on determining the acoustic feature parameters, determining circular space representations for the phase data based on an alignment of the phase data with given axes of the circular space representations; assigning, for the phase data, one or more statistical models adapted to indicate statistical distributions mapped to a circular space, wherein assigning the one or more statistical models includes assigning a decision tree-clustered wrapped Gaussian model configured to identify a sequence of phase probability functions that provide a threshold likelihood of reproducing the speech signal; mapping, based on the circular space representations, the sequence of phase probability functions, and the adapted one or more statistical models, the phase data to linguistic features associated with linguistic content that includes phonemic content or text content; and providing, based on the mapping, a synthetic audio pronunciation of the linguistic content.
7. A non-transitory computer readable medium having stored therein instructions, that when executed by a computing device, cause the computing device to perform functions comprising: receiving a speech signal; determining acoustic feature parameters for the speech signal, wherein the acoustic feature parameters include phase data, wherein determining the phase data involves using a relative phase shift model; based on determining the acoustic feature parameters, determining circular space representations for the phase data based on an alignment of the phase data with given axes of the circular space representations; assigning, for the phase data, one or more statistical models adapted to indicate statistical distributions mapped to a circular space, wherein assigning the one or more statistical models includes assigning a decision tree-clustered wrapped Gaussian model configured to identify a sequence of phase probability functions that provide a threshold likelihood of reproducing the speech signal; mapping, based on the circular space representations, the sequence of phase probability functions, and the adapted one or more statistical models, the phase data to linguistic features associated with linguistic content that includes phonemic content or text content; and providing, based on the mapping, a synthetic audio pronunciation of the linguistic content. 9. The non-transitory computer readable medium of claim 7 , the functions further comprising: determining the phase data based on the phase data being associated with reference time-instants of a glottal cycle in the speech signal.