Meta-learning on synthetic code-switched speech cut word error rate by 17.7% relative on XLS-R
AspireAI community · arXiv (cs.SD, cs.CL)
Code-switched speech — people sliding between languages mid-sentence — is hard to recognize because real recordings are scarce and synthetic speech does not match them well. This work asks a different question than usual: rather than using synthetic speech for ordinary fine-tuning, use it to learn an adaptation-friendly initialization that then transfers to real speech with only one hour of labeled audio. SyRA-CS does this with Reptile meta-learning, meta-training on the synthetic CS-FLEURS subset for each language pair and then adapting on real target speech. Across Encoder-CTC, FastConformer-RNN-T, Attention Encoder-Decoder and Speech-LLM settings on Arabic-, French-, German- and Hindi-English, it improved word error rate over continual fine-tuning in all 16 model-pair comparisons and character error rate in 15 of 16, with relative macro WER reductions of 17.7% for XLS-R and 5.3 to 5.8% for the other three models. The limitation is that the gains vary in size across architectures, language pairs and metrics, and the real-speech adaptation budget is one hour per pair.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.