KurCorpus 2B

KurCorpus 2B is a multidialectal Kurdish text corpus (>2B tokens) for large-scale language modeling and downstream NLP.

Dialects: Sorani (ckb), Kurmanji/Badini (kmr), Hawrami/Gorani (hac)
License: CC BY 4.0
Repo: https://huggingface.co/datasets/abdulhade/Kurdishcorpus
External record: Mendeley Data DOI 10.17632/fb5xhhn6m5.1

TL;DR

Ready for pretraining and finetuning Kurdish LMs
Single field text (UTF-8), offered as large archives or sharded .txt(.gz)
Includes normalization and cleaning (Unicode, orthography, noise removal with placeholders like [URL], [EMAIL])
No official splits; create your own task-specific splits and report dialect coverage

Quickstart

from datasets import load_dataset

# Stream without downloading everything at once (recommended for very large corpora)
ds = load_dataset("abdulhade/Kurdishcorpus", split="train", streaming=True)

for i, ex in enumerate(ds.take(5)):
    print(ex["text"])

Text Normalization (AsoSoft Library)

This repository documents how Central Kurdish text is normalized with the AsoSoft Library before release. The goal is to standardize Unicode, punctuation, numerals, and common web artifacts so downstream tokenizers and language models see clean, consistent text.

Library: AsoSoft Library (C#/.NET) by Aso Mahmudi
Repo: https://github.com/AsoSoft/AsoSoft-Library
Scope: Kurdish Sorani (ckb) primary, with script-agnostic steps for other Kurdish varieties (kmr, hac)

Why normalize

Reduce spurious vocabulary caused by look-alike glyphs and legacy encodings.
Ensure consistent numerals and punctuation for stable tokenization.
Replace privacy-sensitive artifacts like URLs and emails with safe placeholders.
Remove invisible noise (tatweel, zero-widths, control chars) that hurts training.

What the pipeline does

1) Legacy encodings to Unicode (conditional)

Applied only when legacy font artifacts are detected.

AliK2Unicode
AliWeb2Unicode
Dylan2Unicode
Zarnegar2Unicode

2) HTML and web artifacts

ReplaceHtmlEntity converts entities (e.g. " → ").
ReplaceUrlEmail replaces URLs and emails with [URL] and [EMAIL].

3) Unicode standardization and Kurdish-specific fixes

Normalize(...) with deep and additional corrections enabled.

Replace Arabic Presentation Forms with standard code points.
Remove Tatweel U+0640 and stray control/zero-width characters.
Normalize dashes and spaces.
Map visually similar Arabic letters to Kurdish standard forms (e.g. ڪ, ے, ٶ → ک, ی, ؤ).
Kurdish-specific standardization of ە, هـ, ی, ک.
Correct frequent mis-conversions from non-Unicode fonts.
Optionally convert word-initial ر to ڕ.

4) Punctuation and whitespace

NormalizePunctuations(text, separateAllPunctuations=false) ensures no extra spaces around punctuation.
TrimLine trims leading/trailing whitespace including zero-width spaces.

5) Numerals and digit separation

UnifyNumerals(text, "en") normalizes all digits to ASCII 0–9 for tokenizer stability.
SeperateDigits inserts spaces between digits and adjacent letters (e.g. 12کەس → 12 کەس).

Note: For kmr/hac lines, we only apply script-agnostic steps (HTML/entity cleanup, URL/email replacement, Unicode cleanup, punctuation, numerals, trimming). We do not transliterate or run G2P on released text.

Reproducible configuration

We run the following configuration in order. The last step that applies is the one whose conditions are met.

using AsoSoftLibrary;

string NormalizeCkbLine(string text)
{
    // 1) Legacy converters (conditional, heuristic triggers)
    if (LooksLikeAliK(text))      text = AsoSoft.AliK2Unicode(text);
    if (LooksLikeAliWeb(text))    text = AsoSoft.AliWeb2Unicode(text);
    if (LooksLikeDylan(text))     text = AsoSoft.Dylan2Unicode(text);
    if (LooksLikeZarnegar(text))  text = AsoSoft.Zarnegar2Unicode(text);

    // 2) HTML and web artifacts
    text = AsoSoft.ReplaceHtmlEntity(text);
    text = AsoSoft.ReplaceUrlEmail(text); // replaces with [URL], [EMAIL]

    // 3) Unicode standardization (+ Kurdish fixes)
    // changeInitialR=true enables initial ر → ڕ
    text = AsoSoft.Normalize(
        text: text,
        isOnlyKurdish: true,
        changeInitialR: true,
        deepUnicodeCorrectios: true,
        additionalUnicodeCorrections: true,
        usersReplaceList: null
    );

    // 4) Punctuation and whitespace
    text = AsoSoft.NormalizePunctuations(text, separateAllPunctuations: false);
    text = AsoSoft.TrimLine(text);

    // 5) Numerals and digit separation
    text = AsoSoft.UnifyNumerals(text, "en");
    text = AsoSoft.SeperateDigits(text);

    return text;
}

Heuristic detectors like LooksLikeAliK check for characteristic code points and glyph ranges associated with each legacy font family. The converters are applied only when such patterns are present.

Before and after examples

Input : دەقی«کوردی » و ڕێنووس ،((خاڵبەندی )) چۆنە ؟
Output: دەقی «کوردی» و ڕێنووس، «خاڵبەندی» چۆنە?

Input : ژمارەکانی ٤٥٦ و ۴۵۶ و 456
Output: ژمارەکانی 456 و 456 و 456

Input : دەقے شیَعري خـــۆش. ره‌نگه‌كاني خاك
Output: دەقی شێعری خۆش. ڕەنگەکانی خاک

Input : ئێوە &quot;دەق&quot; لە زمانی &lt;کوردی&gt; دەنووسن
Output: ئێوە "دەق" بە زمانی <کوردی> دەنووسن

Input : لە ساڵی1950دا1000دۆلاریان بە 5کەس دا
Output: لە ساڵی 1950 دا 1000 دۆلاریان بە 5 کەس دا

What we do not do

No transliteration or G2P on the released corpus. The text remains in its native script.
No poem meter classification during release processing.
No semantic rewriting beyond canonical character and punctuation normalization.

Dialect coverage policy

ckb: full AsoSoft normalization including Kurdish-specific fixes.
kmr/hac: script-agnostic cleanup only. We avoid ckb-specific letter substitutions to preserve dialectal orthography and phonology.

Quality checks

Character inventory auditing before and after normalization.
Proportion of placeholders [URL], [EMAIL] to detect crawler bias.
Count of removed control and zero-width characters.
Round-trip sampling with spot manual verification on ambiguous lines.
Determinism check: same input produces same output across runs.

Reproducing locally

Install .NET 6 or newer.
Add AsoSoft Library via NuGet in your C# project.
Pipe your text through a console app using the configuration above.

Example console usage:

dotnet run --project NormalizerApp --input data/raw.txt --output data/normalized.txt

Where NormalizerApp calls NormalizeCkbLine for each line.

Parameters you can tune

changeInitialR: set to false if you do not want ر to become ڕ word-initially.
UnifyNumerals target: "en" for ASCII 0–9 or "ar" for Arabic-Indic digits, depending on your tokenizer.
separateAllPunctuations: set to true if you prefer all punctuation to be isolated by spaces for whitespace-tokenized pipelines.

Cite

If you use KurCorpus 2B, please cite:

BibTeX

@dataset{rawf2025kurcorpus2b,
  title   = {KurCorpus 2B: A Multidialectal 2-Billion-Token Corpus for Kurdish Language Modeling},
  author  = {Rawf, Karwan Mahdi and Abdullah, Abdullah and Hussein, Amanj and Mohammed, Haukar},
  year    = {2025},
  version = {1},
  howpublished = {Mendeley Data},
  doi     = {10.17632/fb5xhhn6m5.1}
}