Currently using BP v6.9 in a multi-language environment in which Windows display language is either English or German. Blue Prism client is always in English (to achieve this we had to delete the localization folder).
Our session logs are always in English (except for OS messages those are of course passed through by BP).
Our audit logs have mixed languages. eg login/logout are always in English. Changes to schedules are based on Windows language settings, so either in English or German.
Date and number formats in logs differ depending on local regional settings in Windows and BP client / resource. This affects all types of analysis, querying of log data.
Language in logs should be consistent in all types of logs and for all types of events.
This could be achieved by either always be in English (except OS messages) or according to server language setting.
Even better would be a own BP system language & region settings that are applied to all logs. This way the text and formats may differ to local BP client settings but at least they would be consistent.
(And our colleagues don't need Google translate for messages generated by BP client running on German Windows ;) )