Within Teamwork Desk, you can choose to change which language is used within the ticket reply editor for a specific inbox.
Once you have chosen a new language, spelling errors will be highlighted for the selected language when you are writing ticket replies.
Note: This will not change the language of the Teamwork Desk Interface.
Click your profile icon in the top right of the main navigation bar and select Settings.
In the Settings area, go to the Inboxes tab and choose the inbox you want to update.
When viewing the inbox, select the Edit Inbox subsection from the left sidebar.
In the list of options, go to Email Language. Hover over the field and click the edit pencil to change the selection.
For more information, see: Creating and Using Canned Responses