This interest has been increasing lately with multiple languages being emphasised on both the JVM and the CLR. Groovy obviously supports a polyglot relationship with Java (e.g. A Groovy class can inherit from a Java class which can inherit from a Groovy class). In other cases Groovy reduces the need to introduce multiple languages because it gives you a Groovy syntax where you might otherwise have to introduce a new language, e.g. using GPath instead of introducing XPath, using datasets instead of SQL, AntBuilder instead of Ant XML files and so on. Other features just make integration with other languages a little easier, e.g. Groovy's regex, multi-line string, GString amd template support.
Groovy also has other Polyglot friendly features or integration possibilities: