Structured Sentiment Analysis in Brazilian Portuguese: An Exploratory Study Using BERTimbau

2026-04-12 · Source: Paper Index on ACL Anthology · Field: Technology & Digital — Artificial Intelligence & Machine Learning · Depth: Advanced, short

Summary

An exploratory study introduces a manually annotated dataset of hotel reviews for Structured Sentiment Analysis (SSA) in Brazilian Portuguese, a language currently lacking dedicated resources for this task. The research proposes a baseline approach that fine-tunes the BERTimbau model using a BIO tagging scheme to extract sentiment spans, specifically focusing on the viability of span-level extraction as a foundational step for SSA. Experimental results, derived from a strict train/validation/test split, indicate a span-level F1-score of 48.41 for holder extraction and a macro F1-score of 61.52. The study also delves into linguistic challenges specific to Portuguese, such as implicit subjects (pro-drop), and provides a detailed error analysis, establishing a preliminary baseline for future relation-aware models in the language.

Key takeaway

For research scientists developing NLP models for low-resource languages, this study demonstrates a practical approach to establishing initial baselines for complex tasks like Structured Sentiment Analysis. You should consider starting with span-level extraction using pre-trained language models like BERTimbau and carefully analyze linguistic challenges, such as pro-drop, to inform subsequent relation-aware model development.

Key insights

Span-level sentiment extraction provides a viable baseline for Structured Sentiment Analysis in Brazilian Portuguese.

Principles

• Resource scarcity necessitates exploratory studies.
• Span-level extraction can precede relation modeling.

Method

Fine-tune BERTimbau with a BIO tagging scheme on a manually annotated dataset of hotel reviews to extract sentiment spans, assessing F1-scores for holder extraction and overall macro F1.

In practice

• Annotate domain-specific datasets for SSA.
• Utilize BERTimbau for Portuguese NLP tasks.

Topics

• Structured Sentiment Analysis
• Brazilian Portuguese
• BERTimbau
• BIO Tagging
• Holder Extraction

Best for: Research Scientist, AI Scientist, NLP Engineer

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Editorial summary, takeaway, and curation by AIssential. Original article published by Paper Index on ACL Anthology.