Could you please advise the Platform and Intelligent Hub version that is being used? This will help to diagnose whether there is an issue. 

In Workspace ONE the Language Settings for each Organisation Group can be changed by navigating to Groups & Settings > All Settings > System > Localization > Language Activation within the WS1 UEM console. 

https://docs.vmware.com/en/VMware-Workspace-ONE-UEM/services/System_Settings_On_Prem/GUID-AWT-SYSTEM...