In the latest versions of Word, the following macro gives readibility statistics, and not the spelling dialog. They may fix it, though.
Code:
SpellCheckDisplayClassicSpellCheckDialog()
'Macro created by Stefan Blom, MVP, September 2018
'https://answers.microsoft.com/en-us/msoffice/forum/msoffice_word-mso_win10-mso_o365b/word-2016-how-to-enable-old-style-spell-check/095bf6ce-7adb-4ac9-94c4-dcfe6cfb34af
'
' broken by Microsoft - now displays readibility statistics October 2018
On Error Resume Next
Dialogs(wdDialogToolsSpellingAndGrammar).Show
End Sub
Installing Macros