Niki Loppi


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Dozens of Translation Directions or Millions of Shared Parameters? Comparing Two Types of Multilinguality in Modular Machine Translation
Michele Boggia | Stig-Arne Grönroos | Niki Loppi | Timothee Mickus | Alessandro Raganato | Jörg Tiedemann | Raúl Vázquez
Proceedings of the 24th Nordic Conference on Computational Linguistics (NoDaLiDa)

There are several ways of implementing multilingual NLP systems but little consensus as to whether different approaches exhibit similar effects. Are the trends that we observe when adding more languages the same as those we observe when sharing more parameters? We focus on encoder representations drawn from modular multilingual machine translation systems in an English-centric scenario, and study their quality from multiple aspects: how adequate they are for machine translation, how independent of the source language they are, and what semantic information they convey. Adding translation directions in English-centric scenarios does not conclusively lead to an increase in translation quality. Shared layers increase performance on zero-shot translation pairs and lead to more language-independent representations, but these improvements do not systematically align with more semantically accurate representations, from a monolingual standpoint.


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Second-order Document Similarity Metrics for Transformers
Jarkko Lagus | Niki Loppi | Arto Klami
Proceedings of the 5th International Conference on Natural Language and Speech Processing (ICNLSP 2022)