It might help to keep in mind that Word is a word processing application. It's purpose and primary function is writing down words. Therefore, it's important to have tools like Spell Check in Word to support that purpose.
Access, on the other hand, is an application designed for the creation of relational databases applications. Its primary purpose and function is managing data. It's not quite so important, therefore, to have powerful word processing tools in Access.
That said, of course, there is a value to having a rudimentary kind of spell checking available.
If you are working with massive amounts of text, perhaps an approach that could speed things up might be to export those text fields into a word processing tool, such as MS Word, for spell-checking.
Besides that, I can't really picture a scenario where this would pay off anyway. After all, in most working relational database applications, new records are either added one by one by a data entry person or persons, or they are imported from an external source--and
in that latter case, of course, spell checking could be done much better in that external source. If your users are consistently miss-spelling words while working with your relational database application, I think a better investment of time might be in training
for them....