3. Integration into CAT Tools

Learning Objectives

After completing this section, you should be able to:

Explain how MTUOC-server connects machine translation systems with professional CAT tools.
Install and configure the MTUOC plugins for OmegaT and RWS Trados Studio.
Configure and test the connection between a CAT tool and a running MTUOC-server.
Use machine translation suggestions from MTUOC-server within a CAT-tool workflow alongside other translation resources.

3.0. From MTUOC-Server to the CAT Tool

In the previous sections, we examined two fundamental components of the machine translation workflow. In Section 1, we introduced MTUOC-server as the middleware that manages communication between translation engines and external applications. In Section 2, we deployed open neural machine translation models such as OpusMT and NLLB through the server.

The next step is to make these translation services available within the environment where professional translators actually work: the Computer-Assisted Translation (CAT) tool.

The basic architecture can be represented as follows:

MT model → MTUOC-server → CAT tool → translator

The machine translation model generates the translation, while MTUOC-server makes the translation service accessible to the CAT tool. The translator can then receive MT suggestions directly within the translation environment, alongside other resources such as translation memories.

MTUOC provides dedicated plugins for two CAT tools covered in this section:

OmegaT, a free and open-source CAT tool.
RWS Trados Studio, a commercial CAT tool widely used in professional translation environments.

Although the installation and configuration procedures differ, the underlying principle is the same. The plugin acts as a client of MTUOC-server: it sends source segments to the server and receives the corresponding machine translations.

For this communication to work, the CAT tool needs to know where the server is running. Two parameters are particularly important:

IP address or server name: identifies the computer on which MTUOC-server is running.
Port: identifies the communication endpoint configured for that server.

If MTUOC-server and the CAT tool are running on the same computer, the connection can be entirely local. If the server is running on another computer, the plugin can connect to it using the appropriate server address and port.

Before configuring either CAT tool, make sure that the MTUOC-server you want to use is running.

3.1. OmegaT

3.1.1. OmegaT and Machine Translation

OmegaT is a free and open-source CAT tool. It provides support for translation memories, terminology, machine translation, and other resources used during the translation process.

This section assumes that you are already familiar with the basic OmegaT workflow. If you have not used OmegaT before, consult the OmegaT for CAT Beginners resource listed under Suggested Reading before continuing.

MTUOC-server can be integrated into OmegaT through the MTUOC MT Engine plugin. Once configured, translations generated by MTUOC-server become available directly in OmegaT's Machine Translation pane.

3.1.2. Installing the MTUOC Plugin

Download the MTUOC plugin:

MtuocTranslatePlugin-0.1.0.jar

Place the downloaded JAR file in the appropriate OmegaT plugin directory for your operating system:

Windows: C:\Program Files\OmegaT\plugin
Linux: $HOME/.omegat/plugin
macOS: ~/Library/Preferences/OmegaT/plugins

NOTE: These paths may vary depending on your OmegaT installation and configuration.

Once the JAR file has been copied to the appropriate directory, launch OmegaT.

3.1.3. Configuring the Connection

To configure the MTUOC plugin:

Go to Options > Preferences.

OmegaT Preferences menu

Select Machine Translation in the sidebar.
Select MTUOC MT Engine and click Configure.

MTUOC MT Engine configuration in OmegaT

Enter the connection details for the MTUOC-server you want to use. The server can be running either locally or on a remote computer.

The connection details should correspond to the IP address and port displayed when you started MTUOC-server.

3.1.4. Testing and Using the MT Engine

Once the connection details have been entered, click Test connection.

If OmegaT can communicate correctly with MTUOC-server, the following message will be displayed:

Server connection OK

The MTUOC machine translation engine is now available in OmegaT.

When you work on a translation project, source segments can be sent to MTUOC-server and the resulting translations will appear automatically in the Machine Translation pane.

The translation model used by OmegaT is determined by the MTUOC-server to which the plugin is connected. For example, if the server is running the English–Spanish OpusMT model configured in Section 2, the plugin will receive translations generated by that model.

For additional information about machine translation integration in OmegaT, consult the OmegaT User Manual.

3.2. RWS Trados Studio

3.2.1. Trados Studio and Machine Translation

RWS Trados Studio is a commercial CAT tool that allows translators to combine different translation resources within the same project, including translation memories and machine translation providers.

MTUOC provides a dedicated plugin that allows Trados Studio to connect to MTUOC-server and retrieve machine translation suggestions.

As with OmegaT, the plugin does not run the translation model itself. It sends source segments to the configured MTUOC-server and receives the resulting translations.

3.2.2. Downloading and Installing the MTUOC Plugin

Download the MTUOC plugin corresponding to your version of Trados Studio and unzip the downloaded file.

Before installing a new version of the MTUOC plugin, uninstall any previous version that may already be installed.

Open the uncompressed folder and double-click the plugin installation file:

The installation interface will appear:

Select the appropriate version of Trados Studio and choose where the plugin should be installed. Then click Next and complete the installation.

Unsigned Plugin Warning

Depending on the plugin version, Trados Studio may display a warning indicating that the plugin is unsigned:

If you are installing the MTUOC plugin obtained from the official MTUOC distribution, click Yes to continue.

Some newly released versions of the plugin may temporarily be unsigned while the corresponding signing process is being completed.

3.2.3. Configuring the Connection

Open a Trados Studio project and go to Project Settings.

Select Translation Memory and Automated Translation for either all language pairs or the specific language pair you want to configure.

Select MTUOC-MACHINE TRANSLATION as a translation provider.

Open Settings to access the MTUOC plugin configuration.

The configuration interface contains three main tabs:

General
Connection test
Advanced

General Tab

The General tab contains the basic connection parameters.

Enter:

the IP address or server name of the MTUOC-server;
the port used by that server.

The language pair is not specified in the plugin itself. Each IP address and port combination connects to a particular running MTUOC-server configuration, and the plugin does not verify whether the language pair used by the server corresponds to the language pair of the Trados project.

You should therefore make sure that the MTUOC-server configuration corresponds to the translation direction required by your project.

3.2.4. Testing the Connection

Before using the server in your project, open the Connection test tab:

Enter or paste a source sentence and click Send.

This test allows you to verify that:

Trados can connect to the specified IP address and port;
MTUOC-server is running;
the server can process the request and return a translation.

Testing the connection before beginning a translation project can help distinguish connection problems from problems related to the CAT-tool project itself.

3.2.5. Advanced Settings

The Advanced tab provides additional options for integrating machine translation into the Trados workflow.

Cache

The Keep the cache (days) setting determines how long translations retrieved from MTUOC-server are stored in the plugin cache.

The cache can also be cleared manually using the Delete cache button.

Translation Score

The Score setting assigns a score to machine translation results.

This is particularly relevant when machine translation is used alongside a translation memory. The score allows the MT result to be compared with translation memory matches so that the different translation resources can be combined within the same workflow.

Description

The Description setting determines how translations produced through the MTUOC plugin are identified in the project's SDLXLIFF file.

Available values include:

Unknown
TM
Machine translation
Alignment
Context TM
Adaptative Machine Translation
Nmt
AutomaticTranslation

These settings allow machine translation output to be identified and managed as part of the wider Trados project workflow.

3.2.6. Using MTUOC-Server in a Trados Project

Once the plugin has been configured and the connection tested, activate the MTUOC translation provider in the project. Source segments can then be sent to the configured MTUOC-server, and the returned translations become available alongside the other translation resources in Trados Studio.

If you want to change the underlying translation model — for example, from an OpusMT model to an NLLB model — the change takes place on the MTUOC-server side. The CAT tool continues to communicate with MTUOC-server through the configured IP address and port.

NOTE: If you experience problems installing, updating, or uninstalling the MTUOC plugin, consult the Troubleshooting section of the course.

Key Takeaways

After completing this section, you should remember that:

MTUOC-server acts as a bridge between translation models and professional CAT tools, while the CAT tool itself does not run the translation model.
OmegaT and RWS Trados Studio can connect to MTUOC-server through dedicated plugins using the server IP address and port.
Once connected, machine translation suggestions can be incorporated into the CAT-tool workflow alongside other resources such as translation memories.
The translation model remains separate from the CAT tool: models can be changed on the MTUOC-server side without changing the basic CAT-tool integration architecture.