Building an in-domain SMT system without in-domain parallel data

We address a challenging problem frequently faced by MT service providers: creating a domain-specific system based on a purely source-monolingual sample of text from the domain. We solve this problem by introducing methods for domain adaptation requiring no in-domain parallel data. Our approach yields results comparable to state-of-the-art systems optimized on an in-domain parallel set with a drop of as little as 0.5 BLEU points across 4 domains.

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