For those of us who grew up going to church, Christianese is almost as native of a language to us as the one we speak daily. But are you excluding some of the girls you lead who don't know that language yet?
Imagine how confusing and uncomfortable it would be to start coming to church in junior high or high school and to be surrounded by people who talk about a hedge of protection, Jesus tarrying, being washed in the blood, born again, and restored.
Let's take a look at some of the most common terms Christians use and some ways you can better refer to them and explain them to the girls you lead.
Sacred vs. Secular. How many times do you refer to the culture and to the schools as the "secular world?" Secular is an important word for girls to learn, so keep using it, but take a minute to explain what you mean. Sacred refers to something of God - something set apart, something holy, reverent, or dealing with the church. Secular refers to things, places, or people that are not promoting God - things that are absent of God.
Born again. This expression comes from John 3:3-7 where Jesus said that no one could get to Heaven unless he was born again. Nicodemus was confused (understandably) and didn't know how a person could enter his mother's womb a second time to be born. What Jesus meant is that we become children of God when we give our lives over to Him. We are given new life. We are babies in our journey to be more like God. Babies are fed milk, and baby Christians are fed the fundamentals of what it means to be a Christian. But as babies grow up they begin to eat the same food their parents eat - food of substance like meat, and as Christians mature in their faith they are fed more substantial principles of faith and theology.
Anointing. I'm sure each of you has prayed for your girls that the anointing of the Lord would rest upon them as they finish out their week at school. There's nothing wrong with that. It's powerful. Maybe for the first few times you pray this you could also go into a little more detail about what you mean so that the girls can pick up what the word means in that context. As you use that word in your prayer, ask that God's blessing and favor would be with them and that the people around them would be able to sense that something is different about them and to start asking what sets them apart.
Legalism. Explain that being a Christian isn't about a list of do's and don'ts and a strict way of life. It's not about a rulebook. It's about lining up your thoughts, actions, and words with those of Jesus Christ and about further developing a relationship with Him every day.
Body of Christ. There can be a few interpretations of this. If you are having communion as a small group, make sure the girls understand the biblical background of communion and what the bread and the grape juice signify. In most other small group contexts you'd probably want to explain that all of the people in the congregation of a church, the different departments at a church, and even other churches make up the body of Christ. Use 1 Corinthians 12 as you talk about how all parts are dependent on each other.
The Church. When you go to church (little ‘c') you go to a building. When you are referring to the people that make up the congregation in that church or even all of the Christians in a particular area, you are referring to the Church (big ‘c').
Hedge of Protection. Perhaps you could refer more to walls of protection or angels surrounding them.
Sanctification. This is one that you will really want to make sure your girls understand. Keep using it, but make sure they know that it means being set apart from sin and refers to the process of becoming more like Christ. At the moment of salvation we are set apart for God's purposes and are made clean from our sins, made holy, and are changed. But as we live out each day we mess up and need God to sanctify us and help us grow to be more like Him every day.
Brother or Sister. Let your girls know that this is a title of respect and refers to verses like Mark 3:35 and 2 Corinthians 6:18 that refer to people who are Christians as family.
By now I'm sure your mind is racing with several other words or expressions not listed here, so take a minute to write them down and think about how you could better explain them to the girls you lead. Once your girls are all on the same page, by all means, use them freely! This is not a matter of "dumbing things down" - it's a matter of not assuming anything. You can't assume all of your girls have a church background or have parents who have had a church background and that they are fully grasping the powerful things you are teaching them and praying over them.