Setting Proofing Language in PowerPoint

Lately I've been using PowerPoint a lot and, oftentimes, I need to set the proofing language of a presentation because I'm creating a slide in a language that is different from my Windows and PowerPoint.

So, following a post in StackOverflow I've created a “global” presentation that let me use a macro in all my presentations as this macro is not needed for the execution.

Second, with this post pointing me in the right direction I created the macro below, which I set to my Quick Access Toolbar, and all is well in my little presetation world.

Option Explicit

Public Sub SetProofingLanguageToPortuguese()
    Call SetProofingLanguage(msoLanguageIDPortuguese)
End Sub

Public Sub SetProofingLanguageToEnglishUS()
    Call SetProofingLanguage(msoLanguageIDEnglishUS)
End Sub

Private Sub SetProofingLanguage(langId As MsoLanguageID)

    Dim ppt As Presentation
    Dim sl As Slide
    Dim sp As Shape
    Dim gp As Shape
    
    Set ppt = PowerPoint.ActivePresentation
    
    For Each sl In ppt.Slides
        For Each sp In sl.Shapes
            Call SetShapeProofLang(sp, langId)
        Next
    Next

End Sub

Private Sub SetShapeProofLang(sp As Shape, langId As MsoLanguageID)

    Select Case sp.Type
        Case msoGroup
            Dim shp As Shape
            For Each shp In shp.GroupItems
                Call SetShapeProofLang(shp, langId)
            Next
        Case msoTable
            Dim r As Row
            Dim c As Cell
            For Each r In sp.Table.Rows
                For Each c In r.Cells
                    Call SetShapeProofLang(c.Shape, langId)
                Next
            Next
        Case Default
            If (sp.HasTextFrame) Then
                sp.TextFrame.TextRange.LanguageID = langId
            End If
    End Select

End Sub

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Edited to add: 

Unfortunately something went wrong, and although the macro works and does its job, the Add-In wasn't as successful. I can't seem to be able to make the Quick Access Toolbar buttons to call the macro when clicked, as I explained here.