NLP for languages the industry forgot

Lapia.

Ngambay · spoken by ~1M people in Chad

Sakayo Toadoum Sari

PhD candidate in AI at CRIL-CNRS, Université d'Artois, working on discourse semantics and causal reasoning, and on multilingual evaluation for African languages: whether benchmark numbers actually measure the reasoning they claim to. If your language isn't in the dataset, build the dataset.

See my work Download CV

01 · About

Who I am.

I grew up in Chad speaking a language with almost no digital footprint. Today I build the technology that gives languages like mine one. My research at CRIL-CNRS (UMR 8188) connects two worlds that rarely meet: discourse-level NLP and formal methods, probing how texts echo one another and how causal structure can be extracted from narratives, with formal guarantees rather than heuristics.

A second thread runs alongside it: multilingual evaluation. Having built speech and translation systems for African languages, I keep meeting the same problem, which is that the automatic metrics say very little about whether a model understood anything. That question is what most of my current benchmark work is about.

I teach algorithmics at Université d'Artois. On YouTube, Sakayo Tech brings AI education in French to students across francophone Africa, and my mentorship program supports a first cohort of 20 young innovators in Chad. I've worked with UNICEF, EPFL, CDIAL, and Batazia, and I contribute to the Masakhane and AfricaNLP communities as a researcher and reviewer.

Portrait of Sakayo Toadoum Sari

Lens, France

7+peer-reviewed publications
5+African languages in my research
80+students trained in Chad & Cameroon
2028PhD defense target

02 · Current work

What I'm building.

In progress

PhD Thesis — Intertextuality & Causality

A semantic analysis of discourse bridging NLP with SAT-based formal methods, from echoes between migration narratives to causal network discovery in biographical trajectories.

CRIL-CNRS · ANR HYCI
SIGDIAL 2026

IntertextMigra

Detecting experiential intertextuality in migration narratives. Shows lexical methods beat semantic embeddings on this task, and explains why.

Accepted · Atlanta, August 2026
CORIA-TALN 2026

EvalLLM RAG Challenge

Solo end-to-end French RAG pipeline built under strict compute constraints, scoring above the field mean on all six official metrics.

Accepted · Solo entry
In revision

AfriCOPA

A diagnostic probe asking whether MT quality metrics track causal reasoning in African languages. They correlate with accuracy far more loosely than their use in evaluation assumes.

Revising after INLG 2026 review
Under review

RF-LAD — compact formal explanations

Logical Analysis of Data built into random forest construction via Minimal Support Sets, producing abductive explanations roughly five times smaller than standard forests on microarray data.

AAAI 2027 · under review
Under review

Beyond Separability

Separability and discriminability come apart under LoRA. A set-cover complexity measure guides rank selection, and a contrastive coverage loss improves low-resource and out-of-distribution results.

EACL 2027 via ARR · under review
Ongoing

Formal probing of language models

Probing with inclusion-minimality guarantees: which dimensions a model actually needs to encode a property, certified rather than estimated.

CRIL-CNRS
Ongoing

Decrypt AI — Sakayo Tech

AI education series in French for African students: concepts, careers, and hands-on tools, published twice a week.

YouTube · @sakayotech

03 · Publications

Selected papers.

All publications on Google Scholar

04 · Journey

From N'Djamena to Lens.

2026 — now

PhD Year 2 · CRIL-CNRS, Université d'Artois

First papers accepted at SIGDIAL and CORIA-TALN, with submissions under review at AAAI and EACL. Teaching algorithmics, and working on benchmarks for causal reasoning in African languages.

2025

PhD begins · UNICEF · CDIAL

Joined CRIL on the ANR HYCI project. RCCE consultancy for UNICEF in Chad. Worked on ASR and TTS for African languages at CDIAL, including a human evaluation pipeline with 20+ annotators.

2023

AMMI · EPFL · Batazia · Tec4Tchad

MSc in Machine Intelligence as a Google & Meta Scholar. Research internship at EPFL on polarization detection. NLP engineering at Batazia. Trained 40+ students in Python and ML.

2020

AIMS Cameroon

MSc in Industrial Mathematics as a MasterCard Foundation Scholar.

2017–2019

Physics · Université de N'Gaoundéré

BSc in Applied Physics, then MSc in Physics. First steps in web development and ML at Limbe City Council.

05 · Skills

Tools I work with.

Research

Discourse semanticsCausal reasoning Multilingual evaluationBenchmark design Formal XAISAT / ASP Machine translationRAG

Engineering

PythonPyTorch Hugging FaceFastAPI ASR / TTSFine-tuning & LoRA

Infrastructure

AWS SageMakerDocker SLURM clustersGit / GitHub LaTeX

06 · Contact

Let's talk.

Building something for underserved languages, or want to collaborate on discourse, causality, or African NLP? I'd love to hear about it.