Several months ago I had a conversation with a home schooling parent about curriculum for high school Bible. Previously they had covered Old and New Testament Survey. For the upcoming year they were considering studying a either Hebrew or Greek. One reason for doing this was the course could count both as Bible credit as well as a foreign language if the child decided to attend a public university.
It is true that the best way to study the Bible is in the original language. To do this ideally one needs to learn Hebrew, Aramaic and Greek. Most theologians and Bible students only learn Hebrew and Greek. Hebrew is the language of the Old Testament. If one’s desire is to focus on the Old Testament then Hebrew is more valuable. Hebrew is more difficult than Greek. There is little in common with English and Hebrew. Hebrew reads right to left, not left to right. The Hebrew alphabet has no vowels. The vowels are pointed or dots that where added by the Masoretes. Many words look the same and correctly interpreting them relies heavily on the context of the passage.
Greek is the language of the New Testament. New Testament scholars focus on Greek. Greek is an easier language to learn. Much of the English language comes from Greek. Most people who have attended college are familiar with the Greek alphabet. Knowledge of Greek prefixes, suffixes and roots also makes learning Greek easier.
Greek and Hebrew are equally important to studying the Bible. Greek is more valuable for New Testament scholars while Hebrew is the choice of Old Testament scholars. If one has to select one language to study Greek would be the best starting point. In my opinion Greek would be the best choice.