Anyone can speak the language, can teach the language?
I disagree. Teaching a particular language like for example an English Language is not an easy task because speaking as your ability and skill is not suitable for you to teach it. Actually, there are so many people who can speak language especially when they are native speaker of this language but suddenly whenever I am listening to them and I am trying to criticize them I found their errors semantically, syntactically, and even in it’s phonologically. They’re abiding the rules of grammar. Basically, they can deliver it in excellent way, with their modulated voice and with dynamism and knowing that everybody is interested listening to them. I realized that they can speak the language very well but how they will be able to teach it if they don’t know the proper pronunciation, correct usage of word and also the right order of the word. So, meaning speaking the language is not enough to teach it. It needs more knowledge, effort and hard time to learn about rules, strategies, and techniques about the language first before you teach it instead of simply speaking with it.
In addition, being a teacher of language is not only being good in speaking. You must be particular in every rules, techniques, and strategies that will enable for you to teach it. Also, you need a lot of certificates of training that will serve as your evidence as a teacher of this language.