@inproceedings{hronsky-keuleers-2024-tokenization,
    title = "Tokenization via Language Modeling: the Role of Preceding Text",
    author = "Hronsky, Rastislav  and
      Keuleers, Emmanuel",
    editor = "Gorman, Kyle  and
      Prud'hommeaux, Emily  and
      Roark, Brian  and
      Sproat, Richard",
    booktitle = "Proceedings of the Second Workshop on Computation and Written Language (CAWL) @ LREC-COLING 2024",
    month = may,
    year = "2024",
    address = "Torino, Italia",
    publisher = "ELRA and ICCL",
    url = "https://aclanthology.org/2024.cawl-1.4",
    pages = "23--35",
    abstract = "While language models benefit immensely from their capacity to model large context (i.e., sequence of preceding tokens), the role of context is unclear in text tokenization, which is, in many cases, language model-driven to begin with. In this paper, we attempt to explore the role in three different writing systems and using three different text tokenization strategies (word-based, Morfessor, and BPE). In the first experiment, we examined how the size of context used for predicting the next token affects the ranking of the segmentation strategies i.t.o. language model surprisal. This effect was very writing system specific: minimal in case of English, and rank-reversing due to increased context size and token granularity in case of Turkish and Chinese. In the second experiment, we examined how context alters segmentation hypotheses when using language models to identify word boundaries. In this case, the effect was subtle: using context-aware, rather than context-free segment scores improved boundary recognition accuracy by up to 0.5{\%}, once baseline effects were exploited.",
}

While language models benefit immensely from their capacity to model large context (i.e., sequence of preceding tokens), the role of context is unclear in text tokenization, which is, in many cases, language model-driven to begin with. In this paper, we attempt to explore the role in three different writing systems and using three different text tokenization strategies (word-based, Morfessor, and BPE). In the first experiment, we examined how the size of context used for predicting the next token affects the ranking of the segmentation strategies i.t.o. language model surprisal. This effect was very writing system specific: minimal in case of English, and rank-reversing due to increased context size and token granularity in case of Turkish and Chinese. In the second experiment, we examined how context alters segmentation hypotheses when using language models to identify word boundaries. In this case, the effect was subtle: using context-aware, rather than context-free segment scores improved boundary recognition accuracy by up to 0.5{\%}, once baseline effects were exploited.
Hronsky, Rastislav Keuleers, Emmanuel
Tokenization via Language Modeling: the Role of Preceding Text