Are you looking to change the default language of your SAP Business One Client interface so that the language of all the labels and texts in the UI is modified ? Below is a tip on how to modify the default language.
How to Change the Default Language in SAP Business One ?
To modify the default language in SAP Business One say English to German , launch the SAP Business One .
In the left sidebar , navigate to the screen
Administration > System Initialization > General Settings > Display tab.
You will see an option here to change the language . Select the desired language and click Update .
You are done . Soon you should see the SAP B1 UI reflecting the modified language.