Hi Tamirra,
Your takeaway from the passage was that
Ms. Wheatley's poetry did the opposite of adopting modern English and instead adopted African themes into modern (at the time) English.
Many reading comprehension passages on the LSAT have themes like that, but this passage actually argues something very different. Take a look, for example, at lines 29-30 and lines 49-50. In lines 49-50, The passage says that Wheatley "adopted a foreign language and a foreign literary tradition" that are "replacements" for her past experience. The passage discusses the African oral tradition but does not indicate that Wheatley incorporated them into her work. In lines 29-30, the passage describes how Wheatley could have, but
did not "exploit" the "potential to apply the ideas of a written literature to an oral literary tradition in the creation of an African American literary language."
If you reread the passage slowly, I think you'll see several other indications that Wheatley learned the poetic forms that were popular in English at the time and became proficient in them.
Now moving on to the question, her approach as an (involuntary) immigrant who wrote poetry in the language of her new country and adopted conventions popular in that culture's poetry at the time is similar to a
modern-day Italian immigrant writing in English (rather than Italian) and adopting the forms of
modern American poetry.
I hope this explanation helps!