Background of the issue:
I need to delete all content in the obsolete language, but when I go to WPML Settings > Site Language, deactivate the second language, and try to delete all content, it just gets stuck and doesn’t delete anything.
Symptoms:
When I go to WPML Settings > Site Language, deactivate the second language, and try to delete all content, the process gets stuck and doesn’t delete anything.
Questions:
how to delete all obsolete content from my website correctly?
We have a known issue related to taxonomies, so those will need to be removed manually first. After those are removed, you can remove the rest of the content.
I think that's the issue you might be experiencing here.
Please let us know how things go.
I hope that you will find this information helpful.