Detection and computational analysis of internet hate speech

Hate speech has long been a prevalent issue offline, but with the rise of the internet and social media, its spread has accelerated. The anonymity afforded by these platforms enables individuals to engage in hate speech often without facing substantial consequences. As technology continues to evolve, new opportunities arise to tackle this problem, particularly through the use of natural language processing (NLP). NLP technology can help automate processes that have traditionally been done manually, such as flagging hate speech in online content. Yet, many issues remain unresolved before we can achieve efficient hate speech detection systems. These include foundational challenges, such as defining hate speech, as well as issues that arise at the end of an NLP pipeline, such as evaluating whether a model can generalize. Additionally, the issue of bias in models poses a significant challenge, as biased training data can lead to inaccurate or unfair results. In this thesis, I will focus on addressing these issues. First, I examine the definitions of hate speech and related concepts like toxicity and abusive language, and their impact on re-annotated datasets. I then compare the original and re-annotated labels in terms of robustness and generalization using a BERT-based classifier. Next, I explore the use of hate speech legislation from three countries for annotation, expanding the task of hate speech detection to prosecutable hate speech detection. The results show even law interpretation can be subjective, which has a consequent effect on model training and evaluation. To address this issue, I introduce a semantic componential analysis of hate speech definitions, leading to the creation of the HateDefCon corpus. Moreover, I present a pipeline for generating parallel multilingual hate speech corpora and discuss the associated challenges. The thesis concludes with an examination of textual biases based on the psycholinguistic aspects of harmful language.