People will have remained the same, you will be different. They won't know that you’re different. They might not ask you questions. You have to learn to be ok with people not being that interested in what you’ve learned or how you’ve changed.
Along with this, be bold in just volunteering information. You know what you want to tell them. You know what experiences you've had. There are a lot of people that would want to know, but just have no clue what to ask or where to even start. You'll probably feel this even from your family and closest friends.
You will have to adjust to a “new” normal. Going back home, you won't be able to slide back into normal life. You’re different now. You will be in the process of creating a “new” normal.
This is hard work. And probably more important work than anything you did during the summer. Long lasting change and maturity is what it's all about.
One of the keys in this for me, was integrating the things that I'd learned into my current context. There's not TWO of you. There's just one and you have new things that you are now responsible to bring back into your context.
Oh, and be okay with letting yourself feel the emotions--happy and sad and etc--of the transition. If you need to cry about something, do it really well! That's really the only way I know of to get it over with.
Don't expect people will want to know or talk about it to the extent that you want to talk.
Think about how you can talk about experiences in ways that other people can relate to. Reduce the times you say snobbily "back when I was on my missions trip…" and increase the times you say "last summer…" Internally, this does two things--first, everyone else had a last summer, too. And they'd probably love to talk about it as much as you want to talk about yours. Talk and listen. Second, it helps you to integrate your life. Not two different yous, but one you over the course of time.
But you do need to process. Find people in your world that are good enough friends that will listen to you and set aside times to talk. Keep in touch with other interns and process what its like back home, what you miss, what is frustrating, what brings you joy...
Also, write stuff down--journal, emails, blog, write lists, poems, doodles, funny things, conversations you want to remember. Or draw pictures, write songs, whatever are your ways of remembering stuff. It'll be helpful for next time you go through this same kind of thing. And helpful for remembering treasures and milestones that you don't want to forget.
Think through--realistically--a few people you'd like to stay in contact with and be proactive about it. Think through how to transition your relationship to be current. Talking about things that are currently happening and that you'd like to see happen in the future. If you only ever talk about the "glory days" your friendship won't develop beyond the memory of the past summer.
Remember that Jesus is the same yesterday today and forever. He is the same in every city state place and context. He was with you during the summer and is still with you now. Cry out to him, he will listen, and he will ultimately be the one that will understand.
If you have personal experience returning or living with a returner, we'd love to hear your dos centavos :)