The most important thing is to encourage your child to try to participate and not be embarrassed of mistakes. Mistakes are an important part of learning. We need your child to feel they are capable of improving; we call this a "growth mindset."
Remind your child not to compare themselves to others. Everyone learns differently and at different speeds. It is not a race. The study of a language takes many years. It is more important for them to try their best and to help their classmates than it is to be the best in the class.
Encourage your child to read every night. This can be a paper book or a book on Reading A-Z. Ask your child to talk about the books they read. They can do this in any language!
Have your child tell you stories. Encourage them to tell events in order. Ask them for details.