kulaputra argued that "All human beings are equally proficient in the use of their native language" and I fundamentally disagree. Some people are great orators and/or writers and others are not. This might be a skill which can be developed, but everyone being equally proficient is not an accurate statement, since it can be easily proved people have different levels of vocabulary, experience and education.
Blanket statements about "All human beings" are almost always false simply because of the diversity of the human animal.
I agree there isn't any direct link between skill in L1 and skill in L2, but when you're talking about averages then things can run along a parallel track. I say this simply because the personality traits which make a person good or bad at one skill might make them good or bad at a related skill. So if you're a poor student, dislike studying, dislike reading, dislike puzzles, and dislike speaking with/to others then you're unlikely to become a great orator in any language.
kulaputra wrote:Reading and writing are not language. Language is a natural human faculty, as innate to us as flying is to (most) birds. On the other hand, writing is an artifice that has only existed for less then 2% of the time we have been on this planet as H. Sapiens. The vast majority of people to have ever existed were perfectly illiterate and also perfectly competent in their L1.
Of course in today's world it's great not to be illiterate, but it isn't the same thing as language incompetence, which is the mark of infants and L2 learners.
My objection is you're saying that everyone is equally good at it, which I believe is not an accurate statement. All humans can sing, some couldn't carry a tune in a bucket.