Need to identify a spectral transform to work instead of Short term Fourier Transform (STFT)

I am trying to find a signal processing transform, that allows capturing sequential patterns in sequential data / time series data. I work on natural speech input, so the transform need to have time and spectrum attributes aligning with MFCC coefficients Short-term Fourier transform (STFT) so far fits best with my objective. My work is to detect features or patterns as discrete units (like how a small chunk of speech signal can be mapped to a word or a character) in speech signals. Computations can focus on specific attributes of a speech signal like, (but not limited to), a) speech unit transition patterns - information derived from acoustic or sound characteristics of speech signal. b) speech unit boundary patterns - information derived from acoustic and/or phonological events in speech signals. It could fit into developing a mathematical model that is a variant of Short term Fourier transform (STFT) or something better. Ideally, windowing for extracting discrete units will be at multiple levels - milliseconds to match the standard speech rate and microseconds to match smaller-than-character pattern rates. Output of the function can be vectors, or signal transform functions, or transform coefficients. I will figure out how to map them into smaller-than-word and smaller-than-character (subword) tokens. Main requirement: We need evidence that the transform/function will perform better than STFT. Better with respect to : - the signals or datasets it has been applied to so far, - or in terms of energy density, - or processing and computational complexity o(n) for time series signals, - or in terms of implementation, - or in terms of the function's RoC, etc. Anything anywhere in literature / practical results that says "the transform (or function) performs or represents....etc, better than STFT", is good enough. NOTE: If you know Matlab instead of Mathematics that is also okay. Since this is a small task, I am flexible to give you a fixed budget and let you decide the project duration.