You can use this by either downloading the JAR file, or using Jitpack.
To do so, add the following repository and dependency to your POM file:
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>com.github.rfdj</groupId>
<artifactId>SimpleNLG-NL</artifactId>
<version>1.1</version>
</dependency>
</dependencies>