Abstract: Computer-implemented methods and computing devices for converting spoken language into text. Computer-implemented methods include receiving an input audio signal that includes spoken language uttered by a speaker, analyzing the input audio signal, and determining one or more differences between one or more measured formant values and one or more model formant values. The computer-implemented methods further may include identifying an optimal trained model for processing the input audio signal and/or transforming the input audio signal into a transformed audio signal that more closely matches the trained model. Computing devices for converting spoken language into text include a processing unit and a memory that stores non-transitory computer readable instructions that, when executed by the processing unit, cause the computing devices to perform the computer-implemented methods disclosed herein.