Families from outside the U.S. can absolutely attend camp and we have had campers whose native language is not English attend in the past. Typically, they have enjoyed themselves and been able to successfully participate in camp. Most of our activities are hands-on, so they are able to explore the activities independently or with the support of another camper or one of our staff members. Additionally, there are definitely times when we discover that someone else at camp also speaks the same language (though not always fluently) and can be an extra help.
Below are a few points that will help you to complete registration. First, our registration system will not let you input a physical address from outside of the US. This is because we want to have your local information (i.e. where you are staying while in the US). You can provide the address of your hotel, friends' house, where ever. Also, the fields for Doctor, Dentist, and Health Insurance are required fields. For the Doctor/Dentist, you can simply put in 'None local' and then a fake number 555-555-5555. But the Health Insurance is different.
As a part of registration, we have all parents accept a waiver of liability and assumption of risks stating that they understand they are responsible for providing medical insurance coverage and are responsible for the costs of any medical treatment not covered by medical insurance in the unlikely event of an accident or injury at camp. Acceptance of these terms is a requirement during registration, and there isn't a way for you to bypass that step or for me to make an exception. I know that short-term travel medical insurance does exist, so perhaps that is something you may want to look into.
For payment, we do accept credit cards from outside the US.