Do students from countries that teach native languages considered to be quite difficult (e.g. Japanese) generally take longer to master that language? Or does the power of being surrounded by a particular language at home and in society overcome the difficulty of said language? Are there simply too many factors that influence how well one student learns their native language compared to others?
Another thing: Is the 'difficulty' of a certain language considered completely relative to whatever languages someone already knows, or are some languages universally more difficult?