Should grammar learning precede conversational practice?

[Kennen]

In the process of learning English grammar learners can devote a portion of time at each lesson for learning first fixed thematic conversational phrases that don't require grammar knowledge. Later based on known grammar learners can concentrate more productively on listening, speaking, reading and writing practice on each daily life topic and on thematic vocabulary expansion.
I would argue that first a foreign learner must learn at least major English grammar from a grammar textbook that contains explanations, examples and exercises with answers to them before being able to communicate grammatically correctly in daily life with native speakers of English. It is a good idea for learners to study just one grammar rule (not several rules) at a time followed by usage examples and practising exercises with daily life content that illustrate that particular rule. Gradually English grammar can be learned this way up to the advanced level within two years or even sooner depending on the learner. The duration of each everyday lesson may be between one hour and two hours. Only the right amount of material can be absorbed by the particular learner. Most learners cannot afford more than two hours a day to learn English without strain.

[Sally Olsen]

Check out System Functional Grammar.