Linguistic Identity Leakage: When Language Reveals Identity in Anonymized Text
Paper · 2026 · Wajdi Zaghouani
Summary
Conventional text anonymization removes names, addresses and other explicit identifiers. This position paper argues that the language of a document still exposes its author. Dialect vocabulary, morphology, code-switching habits and stylometric regularities can point to a person's region, social background or community after redaction. The author calls this residual risk Linguistic Identity Leakage (LIL) and the features that carry it Linguistic Personally Identifiable Information (L-PII).
The paper draws on sociolinguistics, stylometry and NLP privacy research. It sketches a preliminary five-category taxonomy of L-PII, illustrated mainly with Arabic dialect data. It also proposes the Identity Inference Risk (IIR) framework for auditing datasets and models for leftover identity risk. Current LLMs, it argues, make such inference cheap and scalable.
The work reports no experiments. Its contribution is conceptual, and IIR has not been implemented. Its value lies in exposing a blind spot of span-level de-identification, especially for small, linguistically distinctive communities. It recommends that dataset documentation and LLM privacy testing account for this risk.
Key points
- Running example: a Tunisian sentence that mixes dialect and French passes NER-based anonymization untouched. It still contains three identity cues that an LLM or dialect classifier could exploit:
- the Tunisian word "barsha";
- a Maghrebi n- verb prefix;
- a switch into French.
- Cited evidence on inference and obfuscation:
- Staab et al. (2024) found that LLMs infer location, income and sex from Reddit profiles with up to 85% top-1 accuracy, and that anonymization and alignment did not prevent this.
- Zhai et al. (2022) showed adversarial attributors cut obfuscation success from 20–30% to 5–10%.
- Cited evidence on dialect granularity: the MADAR Arabic Dialect Corpus covers 25 cities, implying written dialect may reveal a writer's city, not only their country.
- Recommendations:
- treat dialect, sociolect and style as quasi-identifiers in Datasheets for Datasets;
- accompany releases with an IIR audit giving per-category risk scores;
- restrict dialect-rich subsets to vetted researchers;
- test LLMs for demographic inference, beyond memorization and membership inference.
- Limitations stated by the author:
- there is no empirical measurement of LIL;
- the taxonomy comes from conceptual synthesis rather than the Nickerson et al. (2013) method;
- the idea that generative AI could flatten stylistic variation and thereby lower LIL has not been tested.
Institutions
Fields, topics and concepts
📚 Shelves 6The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksArtificial Intelligence · 17,965 worksArts and Humanities · 17,450 worksLanguage and Linguistics · 17,296 worksSocial Sciences · 1,954 worksSociology and Political Science · 626 works
Cite
Cite as Wajdi Zaghouani. 2026. Linguistic Identity Leakage: When Language Reveals Identity in Anonymized Text. Proceedings of the Seventh Workshop on Privacy in Natural Language Processing.
@inproceedings{zaghouani2026linguistic,
title = {{Linguistic Identity Leakage: When Language Reveals Identity in Anonymized Text}},
author = {Wajdi Zaghouani},
booktitle = {Proceedings of the Seventh Workshop on Privacy in Natural Language Processing},
year = {2026},
doi = {10.18653/v1/2026.privatenlp-main.8},
url = {https://doi.org/10.18653/v1/2026.privatenlp-main.8}
}References
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