  Self-supervised learning (SSL) for rich speech representations has achieved
empirical success in low-resource Automatic Speech Recognition (ASR) and other
speech processing tasks, which can mitigate the necessity of a large amount of
transcribed speech and thus has driven a growing demand for on-device ASR and
other speech processing. However, advanced speech SSL models have become
increasingly large, which contradicts the limited on-device resources. This gap
could be more severe in multilingual/multitask scenarios requiring
simultaneously recognizing multiple languages or executing multiple speech
processing tasks. Additionally, strongly overparameterized speech SSL models
tend to suffer from overfitting when being finetuned on low-resource speech
corpus. This work aims to enhance the practical usage of speech SSL models
towards a win-win in both enhanced efficiency and alleviated overfitting via
our proposed S$^3$-Router framework, which for the first time discovers that
simply discarding no more than 10\% of model weights via only finetuning model
connections of speech SSL models can achieve better accuracy over standard
weight finetuning on downstream speech processing tasks. More importantly,
S$^3$-Router can serve as an all-in-one technique to enable (1) a new
finetuning scheme, (2) an efficient multilingual/multitask solution, (3) a
state-of-the-art ASR pruning technique, and (4) a new tool to quantitatively
analyze the learned speech representation. We believe S$^3$-Router has provided
a new perspective for practical deployment of speech SSL models. Our codes are
available at: https://github.com/GATECH-EIC/S3-Router.
