Layer-Wise Feature Distillation with Unsupervised Multi-Aspect Optimization for Improved Automatic Speech Assessment

Self-supervised features have shown promising progress across several domains. In Automatic Speech Assessment (ASA), SSL features have been widely utilized in recent research. However, few studies have dedicated efforts to explore the layerwise features in pre-trained SSL models. Another key challenge in ASA is the high cost of labeling various aspects of speech proficiency, such as content relevance, delivery, and language use. In this paper, we propose three unsupervised subtasks to assist model training in ASA and examine the importance of embeddings from each layer of the acoustic model for various aspects. This provides preliminary research in this area. Extensive experiments demonstrate that model training with our tailored subtasks achieves superior performance in speech proficiency assessment tasks.