Neural TTS Emphasis via Acoustic Embeddings
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Solution Overview
Problem
Existing speech processing systems struggle to accurately reflect emphasis in synthesized speech, which is crucial for natural-sounding human-computer interactions.
Innovation Solution
The system employs an emphasis model that generates acoustic embeddings to modify phoneme embeddings, allowing for natural emphasis in synthesized speech by adjusting duration and other prosodic features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional speech synthesis methods are used, then speech generation is simple and fast, but the synthesized speech lacks natural emphasis and prosody
Solution Approach 1:
The patent embeds multiple levels of neural network models within each other - a phoneme-level emphasis detection model is nested within a word-level model, which is nested within a sentence-level prosody generation model. This nested architecture allows the system to capture emphasis at different granularities while maintaining computational efficiency through shared latent representations.
Solution Approach 2:
The patent transforms the one-dimensional text input into multi-dimensional acoustic embeddings that encode both linguistic content and prosodic features. By projecting text into a higher-dimensional acoustic space, the system can simultaneously represent phoneme identities, emphasis patterns, and prosodic contours, enabling natural-sounding synthesis without requiring separate processing modules.
2Reliability
If emphasis is added to synthesized speech, then naturalness improves, but processing time and computational resources increase
Solution Approach 1:
The patent performs emphasis detection and acoustic embedding generation in advance during the text processing stage, before actual speech synthesis. By pre-computing the emphasis patterns and encoding them into acoustic embeddings, the system avoids real-time computational overhead during speech generation, maintaining both accuracy and efficiency.
Solution Approach 2:
The patent uses pre-trained neural network models that have learned emphasis patterns from large corpora of natural speech. These models copy proven effective prosodic patterns from training data and apply them to new text inputs, avoiding the need to compute emphasis from scratch and significantly reducing processing time while maintaining high accuracy.
Data Source
AI summary
A neural text-to-speech system may be configured to emphasize words. Applying emphasis where appropriate enables the TTS system to better reproduce prosodic characteristics of human speech. Emphasis may make the resulting synthesized speech more understandable and engaging than synthesized speech lacking emphasis. Emphasis may be manually annotated to, and/or predicted from, a source text (e.g., a book). In some implementations, the system may use a generative model such as a variational autoencoder to generate word acoustic embeddings indicating how emphasis is to be reflected in the synthesized speech. A phoneme encoder of the TTS system may process phonemes to generate phoneme embeddings. A decoder may process the word acoustic embeddings and the phoneme embeddings to generate spectrogram data representing the synthesized speech.


