I think in a Healthcare setting this has a lot to do with these types of rules.

Regardless of the fact that most communications in other languages will not be this, there will almost certainly be cases where a second language is used to talk about a patient or coworker in their presence. This builds an outgroup/ingroup dynamic that can undermine confidence in healthcare outcomes and cause patient distress.

Essentially, if some people hear another language being spoken in their presence, and especially if they are in a vulnerable state, they will assume they are being talked about disparagingly or conspired against. Avoiding causing undue distress to patients is a standard of care concern.