9. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, result in the processor performing operations comprising: detecting, via a machine learning algorithm modeling human perception and trained with acoustic parameters from each syllable in a word, incorrect stress patterns in selected acoustic units representing speech to be synthesized, wherein the selected acoustic units comprise phonemes and come from a database of energy-normalized acoustic units that are normalized on a sentence basis; performing a word level analysis of the incorrect stress patterns, a phrase level analysis of the incorrect stress patterns, and a sentence level analysis of the incorrect stress patterns to yield analyses, wherein the analyses are performed in series; and modifying, via the processor and prior to waveform synthesis, the incorrect stress patterns in the selected acoustic units according to the analyses, to yield corrected stress patterns.
9. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, result in the processor performing operations comprising: detecting, via a machine learning algorithm modeling human perception and trained with acoustic parameters from each syllable in a word, incorrect stress patterns in selected acoustic units representing speech to be synthesized, wherein the selected acoustic units comprise phonemes and come from a database of energy-normalized acoustic units that are normalized on a sentence basis; performing a word level analysis of the incorrect stress patterns, a phrase level analysis of the incorrect stress patterns, and a sentence level analysis of the incorrect stress patterns to yield analyses, wherein the analyses are performed in series; and modifying, via the processor and prior to waveform synthesis, the incorrect stress patterns in the selected acoustic units according to the analyses, to yield corrected stress patterns. 12. The system of claim 9 , the computer-readable storage medium having additional instructions stored which, when executed by the processor, result in further operations comprising synthesizing speech according to the corrected stress patterns.