tomekceszke/polish-punctuation-corpus

Polish Punctuation Corpus (Wolne Lektury)

Word-level punctuation labels extracted from 11 Polish literary works, built to train tomekceszke/polish-punctuation-restorer.

Each row is one word and the mark that followed it in the original text.

Column	Type	Meaning
word	string	Lower-cased token, punctuation removed
label	int	1 = nothing follows, 2 = comma, 3 = period

from datasets import load_dataset

ds = load_dataset("tomekceszke/polish-punctuation-corpus")
ds["train"][0]        # {'word': 'chłopi', 'label': 1}

Splits

The split is by document, never by sentence — no phrase can leak from training into evaluation.

Split	Rows	Share	Books
train	828,125	69.2%	7
validation	239,580	20.0%	2
test	128,235	10.7%	2

Label distribution

Heavily imbalanced, which is the central difficulty of the task: four out of five words are followed by nothing at all.

Split	NONE (1)	COMMA (2)	PERIOD (3)
train	668,692 (80.7%)	98,756 (11.9%)	60,677 (7.3%)
validation	191,618 (80.0%)	30,825 (12.9%)	17,137 (7.2%)
test	106,928 (83.4%)	13,133 (10.2%)	8,174 (6.4%)

Any model trained on this without class weighting will learn to predict 1 and stop there.

How it was built

Raw .txt files from Wolne Lektury go through src/preprocess.m:

1. Lower-case the whole text.
2. Strip every character except Polish letters (a-ząćęłńóśźż), whitespace, , and ..
3. Split on whitespace.
4. Take one trailing , or . off each token; that mark becomes the label.

Only commas and periods are modelled. Question marks, exclamation marks and semicolons are removed in step 2 and become NONE.

Known artefact

Step 4 removes exactly one trailing mark, so an ellipsis (… written as ...) leaves a residue: "co.." labelled as PERIOD. About 2% of tokens carry such a leftover character. The corpus is published as it is, because this is the exact data the released model was trained on.

Sources and licences

Every text comes from Wolne Lektury and is either in the public domain or released under the Free Art License 1.3 — the modern translations included, which the foundation commissioned and published under that licence.

Train

Work	Author	Translator	Licence
Chłopi	Władysław Stanisław Reymont	—	Public domain
Lalka	Bolesław Prus	—	Public domain
Nad Niemnem	Eliza Orzeszkowa	—	Public domain
Proces	Franz Kafka	Katarzyna Łakomik	Free Art 1.3
Przedwiośnie	Stefan Żeromski	—	Public domain
Moralność pani Dulskiej	Gabriela Zapolska	—	Public domain
Mały Książę	Antoine de Saint-Exupéry	Agata Kozak	Free Art 1.3

Validation

Work	Author	Translator	Licence
Ziemia obiecana	Władysław Stanisław Reymont	—	Public domain
Rok 1984	George Orwell	Julia Fiedorczuk	Free Art 1.3

Test

Work	Author	Translator	Licence
Syzyfowe prace	Stefan Żeromski	—	Public domain
Tajemniczy ogród	Frances Hodgson Burnett	Jadwiga Włodarkiewiczowa	Public domain

Chłopi and Lalka are used as excerpts; the rest are complete texts. The Wolne Lektury Foundation reserves the rights to its critical editions under art. 99(2) of the Polish Copyright Act — this corpus uses the plain text only. Terms of use: https://wolnelektury.pl/info/zasady-wykorzystania/

Links

• Model trained on this: tomekceszke/polish-punctuation-restorer
• Code: https://github.com/tomekceszke/polish-punctuation-restorer
• Project page: https://tomek.ceszke.com/polish-punctuation-restorer/