They probably went like my previous client through a cycle of starting with a single text file of bad words --> to integrating with one proper swearing service

They probably went like my previous client through a cycle of starting with a single text file of bad words --> to integrating with one proper swearing service (pottymouth, cleanspeak, etc. --> to several services in fallback mode in several languages --> to realising with their traffic that costs a bomb so to back to static files again. Hopefully i18n bundles but probably as you say just in a couple languages. I have always been able to swear everywhere online in Norwegian.