All languages originated informally only. It is exchanged from one generation to another informally and automatically. Languages are originated not from a set of rules, by-laws or even not from text books. Changing an informal and automatically originated language system to a formal system (by making grammar rules & making language as a learning subject) is the reason behind the failures of the conventional and formal way of teaching language.
Instead of teaching a language, giving maximum hearing and talking chances in an informal and real life or practical way is the best and scientific way of acquisition of a language. That means stopping formal teaching of language is the best option for the acquisition of language in people. The formal teaching of words, meaning, spelling, pronunciation etc. creates negative effect only in the learner. Because these type teaching diverts the attention of the speaker in finding meaning, checking pronunciation etc. instead of talking or answering. This principle is applicable for the acquisition of language for all native & non native speakers. The strategy should be same for building language skills in both native & non native language speakers.