This paper aims to investigate the effectiveness of the k-Nearest Neighbor Machine Translation model (kNN-MT) in real-world scenarios. kNN-MT is a retrieval-augmented framework that combines the advantages of parametric models with non-parametric datastores built using a set of parallel sentences. Previous studies have primarily focused on evaluating the model using only the BLEU metric and have not tested kNN-MT in real world scenarios. Our study aims to fill this gap by conducting a comprehensive analysis on various datasets comprising different language pairs and different domains, using multiple automatic metrics and expert evaluated Multidimensional Quality Metrics (MQM). We compare kNN-MT with two alternate strategies: fine-tuning all the model parameters and adapter-based finetuning. Finally, we analyze the effect of the datastore size on translation quality, and we examine the number of entries necessary to bootstrap and configure the index.

This paper illustrates a new methodology based on Test Suites (Avramidis et al., 2018) with focus on Business Critical Errors (BCEs) (Stewart et al., 2022) to evaluate the output of Machine Translation (MT) and Quality Estimation (QE) systems. We demonstrate the value of relying on semi-automatic evaluation done through scalable BCE-focused Test Suites to monitor both MT and QE systems’ performance for 8 language pairs (LPs) and a total of 4 error categories. This approach allows us to not only track the impact of new features and implementations in a real business environment, but also to identify strengths and weaknesses in models regarding different error types, and subsequently know what to improve henceforth.

Frameworks such as Multidimensional Quality Metrics (MQM) provide detailed feedback on translation quality and can pinpoint concrete linguistic errors. The quality of a translation is, however, also closely tied to its utility in a particular use case. Many customers have highly subjective expectations of translation quality. Features such as register, discourse style and brand consistency can be difficult to accommodate given a broadly applied translation solution. In this presentation we will introduce the concept of Business Critical Errors (BCE). Adapted from MQM, the BCE framework provides a perspective on translation quality that allows us to be reactive and adaptive to expectation whilst also maintaining consistency in our translation evaluation. We will demonstrate tooling used at Unbabel that allows us to evaluate the performance of our MT models on BCE using specialized test suites as well as the ability of our AI evaluation models to successfully capture BCE information.

This paper illustrates a new evaluation framework developed at Unbabel for measuring the quality of source language text and its effect on both Machine Translation (MT) and Human Post-Edition (PE) performed by non-professional post-editors. We examine both agent and user-generated content from the Customer Support domain and propose that differentiating the two is crucial to obtaining high quality translation output. Furthermore, we present results of initial experimentation with a new evaluation typology based on the Multidimensional Quality Metrics (MQM) Framework Lommel et al., 2014), specifically tailored toward the evaluation of source language text. We show how the MQM Framework Lommel et al., 2014) can be adapted to assess errors of monolingual source texts and demonstrate how very specific source errors propagate to the MT and PE targets. Finally, we illustrate how MT systems are not robust enough to handle very specific source noise in the context of Customer Support data.