Option Explicit

Private Const mc_CBAR_NAME  As String = "VB-fun-Symbolleiste"
Private Const mc_BTN_TAG    As String = "MY_BUTTON"

Public Sub CreateCommandBar()
  Dim objCBar   As Office.CommandBar
  Dim objCBBtn  As Office.CommandBarButton

  Application.CustomizationContext = ThisDocument

  On Error Resume Next
  Set objCBar = Application.CommandBars(mc_CBAR_NAME)
  On Error GoTo 0
  If Not objCBar Is Nothing Then
    Call ToggleCommandBarButtons
    Exit Sub
  End If

  On Error GoTo err_CreateCommandBar
  Set objCBar = Application.CommandBars.Add( _
        Name:=mc_CBAR_NAME, Temporary:=True)
  With objCBar
    .Visible = True
    .Position = msoBarTop
    .Protection = msoBarNoCustomize + msoBarNoChangeVisible
  End With

  Set objCBBtn = objCBar.Controls.Add(Type:=msoControlButton)
  With objCBBtn
    .Style = msoButtonIconAndCaption
    .Caption = "Sprache &Deutsch"
    .Tag = mc_BTN_TAG & "1"
    .TooltipText = "Spracheinstellung zu Deutsch ändern"
    .FaceId = 790
    .BeginGroup = True
    .OnAction = "ToggleLanguageOptions"
  End With

  Set objCBBtn = objCBar.Controls.Add(Type:=msoControlButton)
  With objCBBtn
    .Style = msoButtonIconAndCaption
    .Caption = "Sprache &Englisch (GB)"
    .Tag = mc_BTN_TAG & "2"
    .TooltipText = "Spracheinstellung zu Englisch ändern"
    .FaceId = 790
    .BeginGroup = True
    .OnAction = "ToggleLanguageOptions"
  End With

  Set objCBBtn = objCBar.Controls.Add _
        (Type:=msoControlButton, ID:=3217)
  With objCBBtn
    .Style = msoButtonCaption
    .Caption = "&Rechtschreibfehler aus-/einblenden"
    .Tag = mc_BTN_TAG & "3"
    .BeginGroup = True
  End With

  Call ToggleCommandBarButtons

exit_Sub:
  On Error Resume Next
  Set objCBBtn = Nothing
  Set objCBar = Nothing

  ThisDocument.Saved = True
  On Error GoTo 0
  Exit Sub

err_CreateCommandBar:
  MsgBox "Fehler #: " & Err.Number & vbCrLf & _
         Err.Description, vbOKOnly + vbCritical
  Resume exit_Sub
End Sub

Sub ToggleCommandBarButtons()
  Dim objCBBtn_German   As Office.CommandBarButton
  Dim objCBBtn_English  As Office.CommandBarButton

  On Error Resume Next

  Set objCBBtn_German = Application.CommandBars.FindControl( _
        Tag:=mc_BTN_TAG & "1")

  Set objCBBtn_English = Application.CommandBars.FindControl( _
        Tag:=mc_BTN_TAG & "2")

  If Err.Number = 0 Then
    Select Case ActiveDocument.Styles("Standard").LanguageID
      Case wdGerman
        objCBBtn_German.State = msoButtonDown
        objCBBtn_English.State = msoButtonUp

      Case wdEnglishUK
        objCBBtn_German.State = msoButtonUp
        objCBBtn_English.State = msoButtonDown

      Case Else
    End Select
  End If

  ThisDocument.Saved = True
  On Error GoTo 0
End Sub

Sub ToggleLanguageOptions()
  Const c_BOOKMARK As String = "DummyBookmark"

  If Not Application.CommandBars.ActionControl Is Nothing Then
    On Error Resume Next
    Application.ScreenUpdating = False

    ActiveDocument.Bookmarks.Add Name:=c_BOOKMARK, _
        Range:=Selection.Range

    Select Case Application.CommandBars.ActionControl.Tag
      Case mc_BTN_TAG & "1"
        ActiveDocument.Styles("Standard").LanguageID = wdGerman
        ActiveDocument.Content.LanguageID = wdGerman

      Case mc_BTN_TAG & "2"
        ActiveDocument.Styles("Standard").LanguageID = wdEnglishUK
        ActiveDocument.Content.LanguageID = wdEnglishUK

      Case Else
    End Select

    With ActiveDocument.Bookmarks(c_BOOKMARK)
      .Select
      .Delete
    End With

    Call ToggleCommandBarButtons
    Application.ScreenUpdating = True
    On Error GoTo 0
  End If
End Sub