It's not easy to express yourself in a foreign language.用外语来表达自己的观点不容易。

He expresses himself easily in English.他轻松地用英语表达自己的观点。

Children may find it easier to express themselves in a letter than in a formal essay.孩子们或许会发现在信件里表达自己的观点要比在正式文章中简单。