Combining Character and Word Embeddings for Affect in Arabic Informal Social Media Microblogs

Word representation models have been successfully applied in many natural language processing tasks, including sentiment analysis. However, these models do not always work effectively in some social media contexts. When considering the use of Arabic in microblogs like Twitter, it is important to note that a variety of different linguistic domains are involved. This is mainly because social media users employ various dialects in their communications. While training word-level models with such informal text can lead to words being captured that have the same meanings, these models cannot capture all words that can be encountered in the real world due to out-of-vocabulary (OOV) words. The inability to identify words is one of the main limitations of this word-level model. In contrast, character-level embeddings can work effectively with this problem through their ability to learn the vectors of character n-grams or parts of words. We take advantage of both character- and word-level models to discover more effective methods to represent Arabic affect words in tweets. We evaluate our embeddings by incorporating them into a supervised learning framework for a range of affect tasks. Our models outperform the state-of-the-art Arabic pre-trained word embeddings in these tasks. Moreover, they offer improved state-of-the-art results for the task of Arabic emotion intensity, outperforming the top-performing systems that employ a combination of deep neural networks and several other features.