I imagine Sivis heirs take an interest in loan words, but I find it humourous considering how they would approach slang!
An interal conflict of those who enjoy watching language mutate, versus the old guard who will never believe that “sick” could define something as being good! A branch of the Speakers Guild having to constantly update their Dictionary of Urban Definitions.

Out of interest, how would you approach Sivis and Thieves Cant? I imagine it would fall within their decryption services if applied for by the authorities. It could be a Cant like Polari in terms of how it was built up over time and used by various groups, whose meaning is known to only those in-the-know. Maybe Thieves Cant even has Sivis origins, something that made it into the wider world past Oversight, so they’re unable to provide translation since it would also be a breach of SOME of their internal codes?