Comparison of character n-grams and lexical features on author, gender, and language variety identification on the same Spanish news corpus

We compare the performance of character n-gram features (n= 3 - 8) and lexical features (unigrams and bigrams of words), as well as their combinations, on the tasks of authorship attribution, author profiling, and discriminating between similar languages. We developed a single multi-labeled corpus for the three aforementioned tasks, composed of news articles in different varieties of Spanish. We used the same machine-learning algorithm, Liblinear SVM, in order to find out which features are more predictive and for which task. Our experiments show that higher-order character n-grams (n= 5 - 8) outperform lower-order character n-grams, and the combination of all word and character n-grams of different orders (n= 1 - 2 for words and n= 3 - 8 for characters) usually outperforms smaller subsets of such features. We also evaluate the performance of character n-grams, lexical features, and their combinations when reducing all named entities to a single symbol “NE” to avoid topic-dependent features.