A Shocking Amount of the Web is Machine Translated: Insights from Multi-Way Parallelism

We show that content on the web is often translated into many languages, and the low quality of these multi-way translations indicates they were likely created using Machine Translation (MT). Multi-way parallel, machine generated content not only dominates the translations in lower resource languages; it also constitutes a large fraction of the total web content in those languages. We also find evidence of a selection bias in the type of content which is translated into many languages, consistent with low quality English content being translated en masse into many lower resource languages, via MT. Our work raises serious concerns about training models such as multilingual large language models on both monolingual and bilingual data scraped from the web. * Corresponding author † Work conducted during an internship at Amazon. 1 Free MT has been available online since late 1997 (Gaspari and Hutchins, 2007) , around the same time that MT researchers began scraping the web for training data (Resnik, 1998) , and commercial systems have been available since the 1970s (Hutchins, 1995) .