A Greek nun, surrounded by Orthodox priests. (CNS photo by Reuters)
The short answer is no. There are many people in the world who do not know Greek, but have a strong understanding of the Bible academically as well as spiritually. It is unlikely that any Christian you know, including your parish priest, is able to read the New Testament in its original Greek. (The Old Testament was written in Hebrew.) Hopefully you could say of at least some people in your life that they have a deep understanding of the Bible. Thanks to the work of editors and translators like those who produced the New American Bible,
someone studying the Bible in English has access to an immense amount of scholarship contained in the introduction, footnotes, and cross-references.
On the other hand, many of the biblical scholars who teach in higher education learned Greek so that they can delve into the linguistic intricacies of the New Testament. Certainly they are privy to nuances of the language that non-Greek readers aren’t, but their role is to share that information so as to help others understand the teachings as fully as possible.