| | --- |
| | dataset_info: |
| | features: |
| | - name: text |
| | dtype: string |
| | - name: lang |
| | dtype: string |
| | - name: name |
| | dtype: string |
| | - name: category |
| | dtype: string |
| | - name: year |
| | dtype: int64 |
| | splits: |
| | - name: train |
| | num_bytes: 412136435 |
| | num_examples: 878 |
| | download_size: 209656175 |
| | dataset_size: 412136435 |
| | configs: |
| | - config_name: default |
| | data_files: |
| | - split: train |
| | path: data/train-* |
| | language: |
| | - chm |
| | - mhr |
| | - mrj |
| | license: cc-by-4.0 |
| | --- |
| | |
| | # Mari Press and School Books Corpus |
| |
|
| | ## Description |
| | This is a text corpus of [Meadow Mari](https://en.wikipedia.org/wiki/Meadow_Mari_language) |
| | and [Hill Mari](https://en.wikipedia.org/wiki/Hill_Mari_language) languages. |
| | The dataset is plain text without any additional annotations except for basic meta data. |
| | Please note, that the texts have been extracted from PDFs, so they are quite dirty. |
| |
|
| | ## Source |
| | The corpus is based on texts from [Mari Lab](https://mari-lab.ru/index.php/Mari-Lab) PDFs |
| | of magazines and school books. |
| |
|
| | ## Composition |
| |
|
| | The first part of the corpus includes the following magazines: |
| |
|
| |
|
| | | name | names_in_corpus | years | languages | |
| | | ---------------- | ---------------- | --------- | ------------------------------------------------------- | |
| | | У вий | U_Viy_* | 1926–1936 | **Meadow Mari** with _rare_ presence of Hill Mari | |
| | | Пиалан илыш | пиалан_илыш_* | 1926–1936 | **Meadow Mari** | |
| | | Родина верч | родина_верч_* | 1942–1945 | **Meadow Mari** | |
| | | Марий альманах | марий_альманах_\*| 1946–1949 | **Meadow Mari** | |
| | | Ончыко | ончыко_* | 1954-2022 | **Meadow Mari** with _occasional_ presence of Hill Mari | |
| | | Марий сандылак | марий_сандалык_* | 2008-2018 | **Meadow Mari** with _occasional_ presence of Hill Mari | |
| | | У сэм | у_сэм_* | 1930-1934 | **Hill Mari** | |
| | | Йакшар знамӹ | йакшар_знамӹ_* | 1935-1936 | **Hill Mari** | |
| | | У сем | у_сем_* | 1990-2018 | **Hill Mari** | |
| |
|
| | Note 1: _У вий_, _Пиалан илыш_, _Родина верч_, _Марий альманах_ and _Ончыко_ are names of the same magazine |
| | in different years. |
| |
|
| | Note 2: writing system had minor changes in 1938, if only modern writing is needed, filter by `year` field. |
| |
|
| | The second part includes school books on geography, mathematics and other subjects from |
| | between 1933-1951. |
| |
|
| |
|
| | ## Preprocessing |
| |
|
| | Due to the fact that those are PDFs, a huge amount of preprocessing has been done to convert them to PDFs. |
| | At the beggining the texts have been split into four categories: |
| | * `clean`: clean PDFs that have a text layer in UTF-8 |
| | * `ocr`: OCR PDFs have an automatically recognized text layer in UTF-8 |
| | * `fix`: broken encoding PDFs that have inconsistent ASCII encoding |
| | * `remap`: slightly broken PDFs that have a text layer in UTF-8 but some charachters are incorrect |
| |
|
| | PDFs from first and second categories have been used as-is. |
| | PDFs from the third categories have been assumed to be in `cp1251` and converted to UTF-8. |
| | For the third and fourth categories, the incorrect symbols have been remapped to the correct ones. |
| |
|
| |
|
| | ## Filtering |
| |
|
| | Sometimes Mari magazines contain sections in Russian language. I have |
| | [trained](https://github.com/OneAdder/mari-llm/blob/master/mari_vs_russian_classifier.py) |
| | a logistic regression classifier on [Meadow-Mari-Russian parallel corpus](https://huggingface.co/datasets/AigizK/mari-russian-parallel-corpora). |
| | It yields zero if a sentence is in Mari and 1 if in Russian. Then I classified each line in sections of PDF texts (separated be two line breaks) |
| | and calculated mean score for each section. Sections that are definitely Russian (>0.8) have been removed. |
| |
|
| | ## Metrics |
| |
|
| |
|
| |
|
| | | | Total | Hill Mari only | Meadow Mari only | No OCR | Modern Writing | |
| | | -------- | ---------- | -------------- | ---------------- | --------- | -------------- | |
| | | texts | 878 | 176 | 563 | 166 | 701 | |
| | | tokens* | 45 576 320 | 5 081 705 | 32 426 529 | 8 192 294 | 41 520 480 | |
| |
|
| | _\*nltk.tokenize.casual.TweetTokenizer not very reliable as there is a lot of rubbish from PDF_ |
| |
|
| | ## Cite |
| |
|
| | ```bibtex |
| | @online{mari_press_and_school_books_corpus, |
| | author = {Andrei Chemyshev and Michael Voronov}, |
| | title = {Mari Press and School Books Corpus}, |
| | year = 2025, |
| | url = {https://huggingface.co/datasets/OneAdder/mari-pdf-corpus}, |
| | urldate = {2025-07-17} |
| | } |
| | ``` |
| |
|
