I do not know what code you are using from Access, but the following might be added once you are in Word...
Should activate the spell check.
If you need to use the legacy spell check dialog...
Code:
If Application.Version < "16.0" Then
Dialogs(wdDialogToolsSpellingAndGrammar).Show
Else
ActiveDocument.CheckGrammar
End If
Classic Spell Check Dialog - Macro to use classic dialog rather than Editor