Social networks have become venues where people can share and spread hate speech, especially when the platforms allow users to remain anonymous. Hate speech can have significant social and cultural effects, especially when it targets specific groups of people in terms of religion, race, ethnicity, culture or a specific social situation such as immigrants and refugees. In this study, we propose a hate speech detection model, BERTurk-DualCL, using a mixed objective with contrastive learning loss that is combined with the traditional cross-entropy loss used for classification. In addition, we study the effects of paralinguistic features, namely emojis and hashtags, on the performance of our model. We trained and evaluated our model on tweets in four different topics with heated discussions from two separate datasets, ranging from discussions about migrants to the Israel-Palestine conflict. Our multi-domain model outperforms comparable results in literature and the average results of four domain-specific models, achieving a macro-F1 score of 81.04% and 58.89% on two- and five-class tasks respectively.

ChatGPT, developed by OpenAI, has made a significant impact on the world, mainly on how people interact with technology. In this study, we evaluate ChatGPT’s ability to detect hate speech in Turkish tweets and measure its strength using zero- and few-shot paradigms and compare the results to the supervised fine-tuning BERT model. On evaluations with the SIU2023-NST dataset, ChatGPT achieved 65.81% accuracy in detecting hate speech for the few-shot setting, while BERT with supervised fine-tuning achieved 82.22% accuracy. This results supports previous findings that show that, despite its much smaller size, BERT is more suitable for natural language classifications tasks such as hate speech detection.

This paper offers an overview of Hate Speech Detection in Turkish and Arabic Tweets (HSD-2Lang) Shared Task at CASE workshop to be held jointly with EACL 2024. The task was divided into two subtasks: Subtask A, targeting hate speech detection in various Turkish contexts, and Subtask B, addressing hate speech detection in Arabic with limited data. The shared task attracted significant attention with 33 teams that registered and 10 teams that participated in at least one task. In this paper, we provide the details of the tasks and the approaches adopted by the participant along with an analysis of the results obtained from this shared task.

Social media posts containing hate speech are reproduced and redistributed at an accelerated pace, reaching greater audiences at a higher speed. We present a machine learning system for automatic detection of hate speech in Turkish, along with a hate speech dataset consisting of tweets collected in two separate domains. We first adopted a definition for hate speech that is in line with our goals and amenable to easy annotation; then designed the annotation schema for annotating the collected tweets. The Istanbul Convention dataset consists of tweets posted following the withdrawal of Turkey from the Istanbul Convention. The Refugees dataset was created by collecting tweets about immigrants by filtering based on commonly used keywords related to immigrants. Finally, we have developed a hate speech detection system using the transformer architecture (BERTurk), to be used as a baseline for the collected dataset. The binary classification accuracy is 77% when the system is evaluated using 5-fold cross-validation on the Istanbul Convention dataset and 71% for the Refugee dataset. We also tested a regression model with 0.66 and 0.83 RMSE on a scale of [0-4], for the Istanbul Convention and Refugees datasets.

ROUGE is a widely used evaluation metric in text summarization. However, it is not suitable for the evaluation of abstractive summarization systems as it relies on lexical overlap between the gold standard and the generated summaries. This limitation becomes more apparent for agglutinative languages with very large vocabularies and high type/token ratios. In this paper, we present semantic similarity models for Turkish and apply them as evaluation metrics for an abstractive summarization task. To achieve this, we translated the English STSb dataset into Turkish and presented the first semantic textual similarity dataset for Turkish as well. We showed that our best similarity models have better alignment with average human judgments compared to ROUGE in both Pearson and Spearman correlations.