Exploiting variety-dependent Phones in Portuguese Variety Identification

摘要

This paper presents a new approach of building a language identification system using a specialized Phone Recognition system followed by Language Modeling (PRLM) to differentiate Portuguese varieties spoken in African Countries from European Portuguese. The system is designed to focus on exploiting the phonotactic information of a single discrimina-tively trained tokenizer for the specific pair of target varieties. In contrast to other PRLM-based methods, the single tokenizer already combines distinctive knowledge about the differences between both target varieties. This knowledge is introduced into a dedicated multiple-stream Multi-Layer Perceptron (MLP) phone recognizer by training mono-phoneme models for two varieties as contrasting phoneme-like classes within a single tokenizer. Significant improvements in terms of identification rate and computational cost were achieved compared to a conventional single tokenizer PRLM-based systems and to the combination of up to five parallel PRLM identifiers. The method is also applied to other varieties of Portuguese yielding similar results.