A question about Eastern Orthodoxy...?

Would I have to learn Greek to join the Greek Orthodox Church, or learn Russian to join the Russian Orthodox Church, and so on?

No.

No, I am a former member of the Russian Orthodox Church. The church conducts services in English. There is some Russian used but it is interpreted.

Contact Father Anthony Nelson in Oklahoma City for more information. He is a very dynamic and interesting man and you could learn a lot from him

Not necessarily. There are a lot of Greek Orthodox and Russian Orthodox parishes in the US whose primary language is English. It depends on where you are located and what the local parish's environment is.

Of course, it would always be helpful to learn a little bit of the language of the particular community you'd be attending. And many of the best theological writings are in the original languages of the Eastern Orthodox countries - but for purposes of entering the Church, it is not a requirement. In fact, there are many "cradle Orthodox" (that is, people whose parents were Orthodox and who were baptized as babies) who don't speak much or even any of the "old country" language. So you'd be in good company if you didn't learn Greek or Russian (or Serbian or Arabic etc. etc. etc.).

I hope this helps! Godspeed on your spiritual journey!

No, but it helps

It is hardly something that you "have" to do, but it sure would not hurt.

You can definitely live a full Orthodox life without learning a second or third language. Many Russian and Greek parishes have services mixed with English, and even if they do not you can purchase books with the Liturgy and such printed in both Greek/Russian and English. Spiritual direction and inspiration is easy to come by as there are many great men and women (including Fr Anthony mentioned above) who speak English and even more books in English about every aspect of Orthodoxy.

Unless you are going to go to Greece or Russia on pilgrimage, don't be worried about your native tongue not being sufficient.

Absolutely NOT.

Jesus Christ is Universal and requires no language.

A lot of churches have placed language and culture ahead of the faith - the Greek Orthodox church being the biggest offender. However, please don't be afraid of the culture.