1. A text-independent speaker recognition system comprising: a front end module embodied in one or more non-transitory computer readable media and executable by at least one computer device to: process an audio signal comprising a current sample of natural language speech; identify a speech segment in the current sample of natural language speech; and create a phonetic representation of the speech segment of the current speech sample; and a back end module embodied in one or more non-transitory computer readable media and executable by at least one computer device to: create a current speaker model based on the phonetic representation of the speech segment of the current speech sample, the current speaker model mathematically representing at least one speaker-specific phonemic characteristic of the current speech sample; and compare the current speaker model to a stored speaker model, the stored speaker model mathematically associating phonetic content with one or more other speech samples; wherein the front end module is to apply a neural network-based acoustic model to associate the speech segment with phonetic content; wherein the front end module is to align the phonetic content of the speech segment with time; and wherein the front end module is to align the phonetic content of the speech segment in lexical units, and the back end module is to compute a distance between at least one of the lexical units of the phonetic content with a similar lexical unit of the stored speaker model.