This MWE2 fragment reads your Xtext grammar and converts it to Langium. If you are using a predefined Ecore model (not generated), it will also be converted to Langium as a type definition file.

P2 Repository: https://typefox.github.io/xtext2langium/download/updates/v0.3.0/

Maven:

<dependency>
    <groupId>io.typefox.xtext2langium</groupId>
    <artifactId>io.typefox.xtext2langium</artifactId>
    <version>0.3.0</version>
</dependency>

Gradle: io.typefox.xtext2langium:io.typefox.xtext2langium:0.3.0

Add the fragment to you Language configuration in the MWE2 file and configure the output path.

language = StandardLanguage {
    name = "io.typefox.Example"
    // ... //

    fragment = io.typefox.xtext2langium.Xtext2LangiumFragment {
        outputPath = './langium'
    }

After running the workflow you will find the generated Langium output in ./langium folder.