Welcome children. Make the classroom feel inviting. Depending on the culture the teacher works with, that can look different for each room. A comforting environment will help children feel safe.
Help children learn in two languages. Find books in other languages. Invite a parent or other family member to come to class, when appropriate. This helps both parents and children relax in their new environment. If you speak the child's language, explain things to him in his native tongue for clarification, even if you need to do it after school or during a time when other students go to a special.
Assign a buddy, especially one who speaks the new student's language. Not only will this help the incoming child, but the buddy acts as a mentor who can show his new friend the ropes. The bilingual child has a go-to person for questions, which helps the teacher.
Make a gradual transition. Go to the student's home. Invite him to talk and play. Then, before the school year starts, ask the whole family to come to your classroom by themselves. That way, the child will come to a more familiar environment on the first day of school.