bitig 0.3.1

Next-generation computational stylometry — a Python replacement for R's Stylo.

---

bitig ("writing, inscription, charter" — from Old Turkic) is a Python package and interactive CLI for authorship attribution, author-group style comparison, and forensic-linguistic analysis. It reimplements the analytical breadth of R's Stylo, then adds a modern NLP pipeline (spaCy, transformer embeddings), a Bayesian layer (PyMC), and a full forensic-evidential toolkit on top.

Named after the bitig, the Turkic word for writing / inscription — the kind chiselled into the 8th-century Orkhon stelae. A bitig was a recorded text bearing a writer's hand; this package looks for that hand.

Architecture

Every layer is sklearn-compatible; every Result carries full provenance (corpus hash, feature hash, seed, spaCy version, timestamp, resolved config), so a study written as study.yaml is reproducible to the exact random draw years later.

Install

uv pip install bitig
python -m spacy download en_core_web_trf

Optional extras:

uv pip install "bitig[bayesian]"    # PyMC + arviz for hierarchical models
uv pip install "bitig[embeddings]"  # sentence-transformers + contextual BERT
uv pip install "bitig[viz]"         # plotly, kaleido, ete3
uv pip install "bitig[reports]"     # weasyprint for PDF export
uv pip install "bitig[turkish]"     # spacy-stanza + Stanza for Turkish pipelines

Quickstart

bitig init my-study
cd my-study
# drop .txt files into corpus/
# add metadata.tsv mapping filename → author, group, year, ...
bitig ingest corpus/ --metadata corpus/metadata.tsv
bitig info
bitig run study.yaml --name demo
bitig report results/demo --output results/demo/report.html

A complete beginner-friendly walkthrough using 9 Federalist Papers (including the disputed No. 50) lives at examples/quickstart/. The full 85-paper analysis reproducing the classic Mosteller & Wallace (1964) result is at examples/federalist/.

Desktop GUI

If you'd rather click than write YAML, bitig ships a NiceGUI + pywebview desktop shell that walks the same workflow — Ingest → Study → Run → Results — plus a dedicated Forensic tab.

uv pip install "bitig[gui]"
bitig gui

This opens a native window with native file pickers; pass --no-native to fall back to a browser tab. From the Study page you can pick the method (Burrows/Cosine/Argamon/… Delta, PCA/MDS/t-SNE/UMAP, Ward/k-means/HDBSCAN, Zeta classic/Eder, bootstrap consensus, classify, Bayesian) and the feature family (MFW, char/word n-grams, function words, punctuation, lexical diversity, readability), set parameters, save study.yaml, run, and view results — figures, parquet tables, and result.json scalars — in one place.

Example output

PCA on 200 MFW, trained on known-author Federalist Papers; the disputed #50 is projected into the same space and lands among the Madison cluster — matching the historical consensus.

Capabilities at a glance

Layer	What's included
Languages	EN, TR, DE, ES, FR — first-class. Turkish via Stanford Stanza (BOUN) through spacy-stanza; the rest via official spaCy _trf pipelines. Per-language function words, readability formulas, and contextual/sentence embedding defaults
Corpus	.txt ingestion + TSV metadata, strict/lenient mode, filter, groupby, content-addressed hashing, language-stamped
Features	MFW, char n-grams, word n-grams, POS n-grams, dependency bigrams, function words, punctuation, readability (English 6 + TR/DE/ES/FR native), sentence length, lexical diversity (eight indices), sentence + contextual embeddings
Methods	Burrows / Eder / Argamon / Cosine / Quadratic Delta; Zeta (classic + Eder); PCA / MDS / UMAP / t-SNE; Ward / k-means / HDBSCAN; bootstrap consensus trees; sklearn classify with stylometry-aware CV; Bayesian Wallace-Mosteller + hierarchical group comparison
Forensic	General Impostors verification, Unmasking, Stamatatos distortion, Sapkota char-n-gram categories, CalibratedScorer, log-LR + C_llr + AUC + c@1 + F0.5u + ECE + Brier + Tippett, PANReport, chain-of-custody Provenance, LR-framed HTML report (ENFSI / Nordgaard verbal scale)
Output	Uniform Result record → JSON + Parquet + figures; Jinja2 HTML / Markdown report; publication-grade matplotlib with 300-DPI colourblind palette

Multi-language support

Five first-class languages behind a single bitig.languages registry — English, Turkish, German, Spanish, French. Language flows through Corpus.language and drives per-language defaults for function words, readability formulas, and embedding models:

uv pip install "bitig[turkish]"
python -c "import stanza; stanza.download('tr')"
bitig init demo-tr --language tr
bitig ingest corpus/ --language tr --metadata corpus/metadata.tsv
bitig run study.yaml --name first-run

Turkish parsing goes through Stanford Stanza (BOUN treebank) wrapped by spacy-stanza — it returns native spaCy Doc objects, so every bitig feature extractor works unchanged. Native readability formulas are implemented for each language (Ateşman + Bezirci–Yılmaz for Turkish, Flesch-Amstad + Wiener Sachtextformel for German, Fernández-Huerta + Szigriszt-Pazos for Spanish, Kandel–Moles + LIX for French). Function-word lists are regenerated reproducibly from Universal Dependencies treebanks via scripts/regenerate_function_words.py. See docs/site/concepts/languages.md and the Turkish tutorial.

Forensic toolkit

Forensic authorship research needs more than attribution — it needs one-class verification, topic-invariant features, and evidential output framed as a likelihood ratio. bitig.forensic ships these as a cohesive layer on top of the analysis methods:

from bitig.forensic import (
    GeneralImpostors, Unmasking,        # verification
    CategorizedCharNgramExtractor,      # Sapkota 2015 topic-invariant features
    distort_corpus,                     # Stamatatos 2013 content masking
    CalibratedScorer,                   # Platt / isotonic calibration
    compute_pan_report,                 # AUC + c@1 + F0.5u + Brier + ECE + (cllr)
)
from bitig.report import build_forensic_report  # LR-framed report template

Every forensic method is classifier-agnostic — pair it with any bitig feature set and any Delta / Zeta / classify method. Every Result can carry six optional chain-of-custody metadata fields (questioned_description, known_description, hypothesis_pair, acquisition_notes, custody_notes, source_hashes) so a report traces back to its source material. See src/bitig/forensic/ for the full surface.

Documentation

Full MkDocs Material site — https://fatihbozdag.github.io/bitig/

• Getting started — install, five-command quickstart
• Concepts — Corpus / Features / Languages / Methods / Results & provenance
• Languages — EN / TR / DE / ES / FR registry, adding a sixth language
• Forensic toolkit — verification, calibration, topic-invariance, PAN evaluation, reporting
• Turkish tutorial — end-to-end Turkish authorship walkthrough
• PAN-CLEF verification tutorial — end-to-end runnable pipeline
• Federalist tutorial — reproduce Mosteller & Wallace (1964)
• CLI + API reference

Serve locally:

uv pip install "bitig[docs]"
mkdocs serve             # http://127.0.0.1:8000

CI (.github/workflows/docs.yml) builds the site strictly on every push + PR and deploys to GitHub Pages on every merge to main.

Status

Phase 5 landed — visualisation, Jinja2 reports, declarative runner (bitig run), and a Rich-based interactive bitig shell.

Forensic phase landed — six additions (General Impostors, LR + calibration + evaluation metrics, Sapkota categories + Stamatatos distortion, Unmasking, chain-of-custody + forensic report template, PAN harness).

Multi-language phase landed — first-class support for English, Turkish, German, Spanish, French behind a bitig.languages registry. Turkish parses through Stanford Stanza (BOUN treebank) via spacy-stanza, returning native spaCy Doc objects so every feature extractor works unchanged. Native readability formulas per language (Ateşman + Bezirci–Yılmaz for Turkish, Flesch-Amstad + Wiener Sachtextformel for German, Fernández-Huerta + Szigriszt-Pazos for Spanish, Kandel–Moles + LIX for French). Function-word lists generated reproducibly from UD closed-class tokens.

Docs site landed — MkDocs Material site with Concepts, Forensic toolkit, Federalist + PAN-CLEF + Turkish tutorials, and CLI/API reference, backed by a comprehensive automated test suite (see the badge above).

Docs site is multilingual — English (default) and Turkish (/tr/) launched via mkdocs-static-i18n; DE/ES/FR infrastructure ready, translation content deferred.

Remaining — PyPI publish.

See docs/superpowers/specs/2026-04-17-bitig-stylometry-package-design.md for the full design.

License

BSD-3-Clause. See LICENSE.

Citation

If you use bitig in published work, please cite it — see CITATION.cff.

References

The forensic toolkit implements methods from the following peer-reviewed sources:

• Koppel, M., & Winter, Y. (2014). Determining if two documents are written by the same author. JASIST, 65(1), 178–187.
• Koppel, M., & Schler, J. (2004). Authorship verification as a one-class classification problem. Proceedings of ICML 2004, 489–495.
• Sapkota, U., Bethard, S., Montes-y-Gómez, M., & Solorio, T. (2015). Not all character n-grams are created equal. Proceedings of NAACL-HLT 2015, 93–102.
• Stamatatos, E. (2013). On the robustness of authorship attribution based on character n-gram features. Journal of Law and Policy, 21(2), 421–439.
• Brümmer, N., & du Preez, J. (2006). Application-independent evaluation of speaker detection. Computer Speech & Language, 20(2–3), 230–275.
• Peñas, A., & Rodrigo, A. (2011). A simple measure to assess non-response. Proceedings of ACL-HLT 2011, 1415–1424.
• Platt, J. C. (1999). Probabilistic outputs for SVMs and comparisons to regularized likelihood methods. Advances in Large Margin Classifiers, 61–74.
• ENFSI (2015). Guideline for evaluative reporting in forensic science; Nordgaard, A., Ansell, R., Drotz, W., & Jaeger, L. (2012). Scale of conclusions for the value of evidence. Law, Probability and Risk, 11(1), 1–24.