Sub TestQuotes()
Dim oPara As Paragraph
For Each oPara In ActiveDocument.Paragraphs
  With oPara.Range
    If (Len(.Text) - Len(Replace(.Text, Chr(34), vbNullString))) Mod 2 <> 0 Then
      .Select
      MsgBox "Selected paragraph has unmatched plain quotes", vbExclamation
      Exit Sub
    End If
    If Len(Replace(.Text, Chr(147), vbNullString)) <> Len(Replace(.Text, Chr(148), vbNullString)) Then
      .Select
      MsgBox "Selected paragraph has unmatched smart quotes", vbExclamation
      Exit Sub
    End If
  End With
Next
End Sub