Hello @isakatirci. I cannot help you without more context. How do you try to use Lingua? Which JVM language do you use and which runtime environment? Please show me some code and the complete stacktrace of the error you got. Thanks.

openjdk13:x86_64-debian-jre-13.0.2_8 same issue.

Could fix it by manually adding the
runtimeOnly 'org.jetbrains.kotlin:kotlin-stdlib:1.4.10'
runtimeOnly 'org.jetbrains.kotlinx:kotlinx-serialization-json-jvm:1.0.0'
dependencies.

This is a workaround that does not work on all machines though. This is not a machine or environment dependent problem, it's an issue in the Lingua dependencies and it has been in there for quite a while. It also can cause other related errors, depending on what kotlin dependencies you add.

@pixartist It seems that adding the kotlinx-serialization library to Lingua was not such a good idea. 259 open issues, 66 open bugs. Oh dear! I think I will switch to a more reliable Java json serialization library in the next major release. Then those problems should be gone hopefully. Thanks for letting me know.

I hope that I've fixed this now.