Your machine must have an environment variable setting “LANG=nl_NL.UTF-8”, possibly set by Windows or some other software. Gramps is using that to choose the language to display, but doesn’t have the translations installed for that language (some of the addons may have their own Dutch translations and have their output show up in Dutch).
To avoid Dutch and use English instead, you will have to modify that variable to LANG=en_GB.UTF-8 for your whole machine or at least for Gramps.
To do it in a startup shortcut, modify the shortcut Target to
'C:\Windows\System32\cmd.exe /c “SET LANG=en_GB.UTF-8 && START /D ^“C:\Program Files\GrampsAIO64-5.1.3^” gramps.exe”
That should start Gramps with English always.