ARTHUR SANTANA, Ph.D.

Computational Linguist | NLP & LLM Systems | AI Evaluation & Quality | Prompt Engineering
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Arthur Santana, Ph.D.

Computational Linguist | NLP & LLM Systems | AI Evaluation & Quality | Prompt Engineering
  • email arthurpereirasantana@gmail.com
  • language https://arthurpsantana.github.io/

Hello! I am a computational linguist based in São Paulo, Brazil, with over eight years of experience building NLP and LLM systems, multilingual evaluation pipelines, semantic annotation frameworks, and AI quality processes for large-scale language technologies. I currently work as an AI Quality Assurance Specialist at Decagon (via Mercor) and as an Applied NLP Engineer at the Center for Curriculum Redesign, where I design multi-LLM evaluation pipelines and hallucination-detection systems for AI-generated content. I have a PhD in linguistics from the University of São Paulo, with most of my academic work focused on Phonology. My background also spans NLU/NLG grammar development, ASR and TTS speech technologies, prompt engineering, and language data analysis, built up across roles at Google Brazil and Cerence. For more information, please download my CV in PDF below.

Work Experience

D
AI Quality Assurance Specialist
Decagon (via Mercor)
Nov/2025 - current

As an AI Quality Assurance Specialist, I'm currently responsible for:

C
Applied NLP Engineer
Center for Curriculum Redesign
Oct/2024 - current

As an Applied NLP Engineer, I'm currently responsible for:

Q
Quality Controller
Telus Digital
Jun/2025 - Nov/2025

As a Quality Controller, I was responsible for:

S
Senior Linguist
Google Brazil (via Telus Digital)
Oct/2023 - Jun/2025

As a Senior Linguist, I was responsible for:

N
NLU Language Developer
Cerence (via Maize)
Jun/2022 - Aug/2024

As an NLU Language Developer, I was responsible for:

A
Associate Linguist
Google Brazil (via Telus Digital)
Sep/2018 - Sep/2023

As an Associate Linguist, I was responsible for:

P
Computational Linguist
Portuguese International Institute
Jan/2022 - Jul/2022

Part of my responsibilities as a Computational Linguist:

T
Teacher's Assistant
University of São Paulo
2015 - 2019

As a teacher's assistant, I:

E
English Teacher
English for Business, São Paulo
2013 - 2017

As an English teacher, I:

E
English Teacher
Cultura Inglesa, São Luís
2011 - 2013

As an English teacher, I:

Education

P
PhD in Linguistics
University of São Paulo
2015 - 2019

Advisor: Raquel Santos
Project: Unstressed vowel neutralization in Brazilian Portuguese

Visiting Exchange Scholar
University of Southern California
Jul 2017 - Jun 2018

Supervisor: Rachel Walker
Grant: International Visiting Scholar Grant - Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

M
M.A. in Linguistics
University of São Paulo
2013 - 2015

Advisor: Raquel Santos
Project: Postonic mid-vowel alternation in Brazilian Portuguese

B.A. in Letters
Federal University of Maranhão
2008 - 2013


Journal articles, book chapters, and conference proceedings

2018

SANTANA, Arthur. The status of unstressed lax-mid vowels in northern dialect of Brazilian Portuguese. Revista Linguíʃtica. [link]

SANTANA, Arthur. The role of phonological processes in defining the vowel inventory of Brazilian Portuguese. Acta Linguistica Academica, v. 6, p. 69-86, 2018. [link]

2016

SANTANA, Arthur. Uma abordagem fonológica para as postônicas não-finais. Domínios de LinguaGem, v. 10, p. 494-518, 2016. [link]

2014

BEZERRA, José de Ribamar Mendes ; SANTANA, Arthur. A redução de proparoxítonas no falar maranhense. In: RAZKY, Abdelhak, LIMA, A. F. de, OLIVEIRA, M. B. de, COSTA, E. O. da. (Org.). Estudos sociodialetais do português brasileiro. 1ed.São Paulo: Pontes, 2014, v. 1, p. 31-47.

2013

SANTANA, Arthur; BEZERRA, José de Ribamar Mendes . Proparoxítonos e estratégias de redução com base no corpus do ALiMA. Cadernos de Pesquisa, v. 20, p. 79-88, 2013.

SANTANA, Arthur. A permanência da tônica em variantes proparoxítonas no falar maranhense. In: RAMOS, Conceição et al. (Orgs.). O português falado no Maranhão: múltiplos olhares. São Luís: EDUFMA, 2013.

2012

SANTANA, Arthur. A síncope revisitada: análise com base no corpus do ALiMA. Littera Online, v. 5, p. 50-68, 2012.

SANTANA, Arthur.O apagamento das postônicas não-finais no falar maranhense. In: IV Seminário Internacional de fonologia, 2012, Porto Alegre. Anais do IV Seminário Internacional de fonologia. Porto Alegre: Editora da UFRGS, 2012.

SANTANA, Arthur; BEZERRA, José de Ribamar Mendes . A neutralização das postônicas não finais no falar maranhense: uma análise preliminar. In: II Congresso Internacional de Dialetologia e Sociolinguística, 2012, Belém. Diversidade linguística e política de ensino: anais. São Luís: EDUFMA, 2012. p. 2335-2343.

2011

SANTANA, Arthur. O livro didático do português: uma análise da oralidade. Littera.

SANTANA, Arthur. Variação de proparoxítonas: traços da identidade popular no falar maranhense. III Seminário Linguagem e identidades: múltiplos olhares, 2011.

2010

SANTANA, Arthur. 'Risca o fósqui que a lâmpida apagô': um estudo geosociolinguístico das proparoxítonas no falar maranhense. I Congresso Internacional de Dialetologia e Sociolinguística, 2010.

SANTANA, Arthur. Apócope em proparoxítonos: um estudo preliminar. I Congresso Internacional de Dialetologia e Sociolinguística, 2010.

Conference Presentations

2018

Is there reduction via laxing in northern dialects of Brazilian Portuguese? Generative Linguistics in the Old World - GLOW 41 (Budapest, Hungary. April, 2018) [poster]

Syncope and the canonical foot in Brazilian Portuguese. 7th Hispanic and Luso-Brazilian Linguistics Conference (Tempe, Arizona. March, 2018)

The status of unstressed lax-mid vowels in northern dialect of Brazilian Portuguese. Experimental Portuguese Linguistic (Toronto, Canada. April, 2018) [slides] [abstract]

2016

The role of phonological processes in the vowel inventory of Brazilian Portuguese. Old World Conference in Phonology (OCP 13, 2016) [abstract][poster]

2015

Neutralization of non-final postonic mid vowels in Brazilian Portuguese: assimilation or feature deletion? Phonetics and Phonology in Europe (PAPE 2015) [abstract][poster]

Uma abordagem fonológica para as postônicas não-finais. II Encontro intermediário do GT de Fonética e Fonologia da ANPOLL. [programação]

Vogais medias em dialetos nordestinos: as postônicas não-finais em São Luís. 63 Seminário do GEL [resumo]

Projects

R
Reduction via laxing in northern dialect of Brazilian Portuguese
2015 - 2019

Brazilian Portuguese (BP) has an inventory of seven vowels in stressed syllable /a, ɛ, e, i, ɔ, o, u/. The contrast between lax /ɛ, ɔ/ and tense vowels /e, o/ is lost in unstressed contexts.

E
External Sandhi in Brazilian Portuguese
(with Raquel Santos)
2017 - Ongoing

Previous studies of external sandhi in Brazilian Portuguese have proposed the existence of three categorical process targeting adjacent vowels in word boundaries

P
Postonic mid-vowel alternation in Brazilian Portuguese
2013 - 2015

Brazilian Portuguese has a seven-vowel system in stressed position /a, ɛ, e, i, ɔ, o, u/, which is neutralized in unstressed syllables.

S
Syncope in Brazilian Portuguese
2010 - 2013

Syncope in BP can be defined as a variable process that deletes the vowel in non-final postonic syllables (eg. [ˈah.vo.ɾɪ] ~ [ˈah.vɾɪ] ‘tree’).