Please read the linked threads.
See
Install/Employ VBA Procedures (Macros) by Greg Maxey.
Here is a macro that will change the language setting for everything in a document to English UK:
Code:
Sub ProofingLanguageEnglishUKAllStory() ' based on field updater by Greg Maxey
' https://gregmaxey.com/word_tip_pages/word_fields.html
' Charles Kenyon 6 November 2018
' https://answers.microsoft.com/en-us/msoffice/forum/all/force-all-documents-to-be-edited-in-uk-english/df6d1f8e-5426-49d9-bea0-5620d0208294
' Changes proofing language to English UK in all stories of document
' Language IDs https://docs.microsoft.com/en-us/office/vba/api/word.wdlanguageid
Dim rngStory As Word.range
Dim lngValidate As Long ' do not know purpose of this
Dim oShp As Shape
Let lngValidate = ActiveDocument.Sections(1).Headers(1).range.StoryType
For Each rngStory In ActiveDocument.StoryRanges
'Iterate through all linked stories
Do
On Error Resume Next
Let rngStory.LanguageID = wdEnglishUK
Select Case rngStory.StoryType
Case 6, 7, 8, 9, 10, 11
If rngStory.ShapeRange.Count > 0 Then
For Each oShp In rngStory.ShapeRange[/HTML]
If oShp.TextFrame.HasText Then
Let oShp.TextFrame.TextRange.LanguageID = wdEnglishUK
End If
Next
End If
Case Else
'Do Nothing
End Select
On Error GoTo -1
'Get next linked story (if any)
Set rngStory = rngStory.NextStoryRange
Loop Until rngStory Is Nothing
Next
End Sub
You could attach the macro to a keyboard shortcut or a QAT button if you want.