Twentieth century linguists have spent great energy devising efficient instruction techniques for many of the world's languages and one of the greater efforts has focused on the teaching of Mandarin Chinese. If you are considering study of Chinese or have already begun, why not seek out teachers who have benefited from the knowledge and experience of their predecessors through formal training.
Language learning is not primarily an intellectual pursuit. Babies do it best. Adults learning foreign languages cannot do so without a fair idea of what needs to be learned, but physical practice of speaking actually consumes much more time than is spent thinking about how to speak.
Language learners pay teachers think of them. The teacher is more than a voice to imitate. We can buy a radio if we merely want to hear foreign languages clearly and correctly. We want to learn from native speakers, but we must distinguish between native speakers and trained teachers. No one disputes the fluency of an articulate five year old in his native tongue, but few would pay to pursue language studies under his instruction. Why then pay tuition to older native speakers who have spent little more time than five year olds familiarizing themselves with the specialized techniques mastered by trained, intelligent and experienced instructors which best assure successful language learning?
Successful language learning is not a happy accident but results from collaboration between motivated, alert students and trained, skillful teachers. C.L.I. has the teachers. What kind of student are you?