Sentence boundary detection sounds boring. Split on . ? ! , done, right? Anyone who has tried knows otherwise. Abbreviations, decimals, URLs, nested quotes, ellipsis, legal citations, biomedical jargon—each one turns "split text" into a language-specific puzzle. Two Python libraries tackle this problem with different philosophies. pysbd has been the go-to since 2020 with 22 languages, ported from Ruby's pragmatic segmenter [1]. yasbd-lib is newer, covers 39 languages, and takes a dif...