Recovering the Zipfian Distribution in Unsupervised Term Discovery
Unsupervised term discovery involves segmenting unlabelled speech into word- or syllable-like units and clustering these into a lexicon of candidate types. True lexicons follow a Zipfian distribution, yet the dominant centre-based clustering approach -- K-means -- produces a more uniform distribution due to an inductive bias toward spherical clusters. In this paper we revisit graph-based clustering as a bottom-up alternative, where segment embeddings are connected by pairwise similarity and partitioned using the Leiden algorithm. We show that graph clustering substantially outperforms centre-based approaches (K-means, GMM, BIRCH) in both word- and syllable-level lexicon discovery across t...
| Authors | Danel Slabbert, Simon Malan, Herman Kamper |
|---|---|
| Primary category | eess.AS |
| Published | 9 June 2026 |
| Last updated at source | 24 September 2026 |
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