The rapid proliferation of hate speech on social media poses significant challenges to maintaining a safe and inclusive digital environment. This paper presents a comprehensive review of automatic hate speech detection methods, with a particular focus on the evolution of approaches from traditional machine learning and deep learning models to the more advanced Transformer-based architectures. We systematically analyze over 100 studies, comparing the effectiveness, computational requirements, and applicability of various techniques, including Support Vector Machines, Long Short-Term Memory networks, Convolutional Neural Networks, and Transformer models like BERT and its multilingual variants. The review also explores the datasets, languages, and sources used for hate speech detection, noting the predominance of English-focused research while highlighting emerging efforts in low-resource languages and cross-lingual detection using multilingual Transformers. Additionally, we discuss the role of generative and multi-task learning models as promising avenues for future development. While Transformer-based models consistently achieve state-of-the-art performance, this review underscores the trade-offs between performance and computational cost, emphasizing the need for context-specific solutions. Key challenges such as algorithmic bias, data scarcity, and the need for more standardized benchmarks are also identified. This review provides crucial insights for advancing the field of hate speech detection and shaping future research directions.

Online reviews are one of the main influencers of hotel purchase decisions. This study performs an analysis of reviews extracted from well-known online review sources in combination with hotel sales data and concludes that ratings differ according to the language of reviews. Data science tools have been applied to English, Spanish, and Portuguese reviews, revealing that reviews written in English achieve higher ratings when compared with Spanish or Portuguese reviews. A new visualization method is proposed to quickly depict the sentiment of main topics mentioned in reviews, clearly revealing that not all customers are influenced by reviews in the same way or look for the same things in a hotel. This study has great implications for online reviews research and for hotel management as it clearly shows that language can be used to identify preferences of guests from different origins and because it gives hoteliers more information on how to provide a better service according to guests’ cultural background.

Purpose: This paper aims to develop a model to predict online review ratings from multiple sources, which can be used to detect fraudulent reviews and create proprietary rating indexes, or which can be used as a measure of selection in recommender systems.Design/methodology/approach: This study applies machine learning and natural language processing approaches to combine features derived from the qualitative component of a review with the corresponding quantitative component and, therefore, generate a richer review rating.Findings: Experiments were performed over a collection of hotel online reviews – written in English, Spanish and Portuguese – which shows a significant improvement over the previously reported results, and it not only demonstrates the scientific value of the approach but also strengthens the value of review prediction applications in the business environment.Originality/value: This study shows the importance of building predictive models for revenue management and the application of the index generated by the model. It also demonstrates that, although difficult and challenging, it is possible to achieve valuable results in the application of text analysis across multiple languages.

This paper focuses on the tasks of recovering capitalization and punctuation marks from texts without that information, such as spoken transcripts, produced by automatic speech recognition systems. These two practical rich transcription tasks were performed using the same discriminative approach, based on maximum entropy, suitable for on-the-fly usage. Reported experiments were conducted both over Portuguese and English broadcast news data. Both force aligned and automatic transcripts were used, allowing to measure the impact of the speech recognition errors. Capitalized words and named entities are intrinsically related, and are influenced by time variation effects. For that reason, the so-called language dynamics have been addressed for the capitalization task. Language adaptation results indicate, for both languages, that the capitalization performance is affected by the temporal distance between the training and testing data. In what regards the punctuation task, this paper covers the three most frequent punctuation marks: full stop, comma, and question marks. Different methods were explored for improving the baseline results for full stop and comma. The first uses punctuation information extracted from large written corpora. The second applies different levels of linguistic structure, including lexical, prosodic, and speaker related features. The comma detection improved significantly in the first method, thus indicating that it depends more on lexical features. The second method provided even better results, for both languages and both punctuation marks, best results being achieved mainly for full stop. As for question marks, there is a small gain, but differences are not very significant, due to the relatively small number of question marks in the corpora.