A Common Misconception
The acquisition of the grammatical system of a language is probably the most complex aspect in the foreign language learning process. The problem is that it cannot be taught, a teacher can only support a learner in this process.
Learning about the grammatical system on the other hand is different and the teacher can help a learner with that. However, it is important to know that learning grammar does not necessarily lead to acquisition.
So how does the acquisition of grammar work?
Acquisition means that a learner is able to use a grammatical aspect proficiently in speaking, reading, writing and listening without any conscious effort and without having to think about the grammatical feature and its rules.
Easy: the Plural of Nouns
An intermediate learner of English will not need any conscious effort in getting the plurall of nouns correctly because they have managed to acquire this feature of the language already.
Very difficult: German adjective endings
An intermediate learner will however not have acquired the complex tense system of the English language. This is a good example of how learning does not necessarily lead to acquisition. Just because the students are aware of the rules governing the tense system and have been provided with explicit explanations and grammar tables and given plenty of opportunities to memorise and apply the rules, does not mean that they can use the tenses proficiently.
What does the research say?
The biggest problem in foreign language teaching is exactly this misconception, which leads to a heavy focus on explicit grammar teaching and grammatical accuracy and is hurting the students in their language learning process more than it is helping them.
The research of the past 20 years indicates that mastering the grammatical system of a foreign language is indeed a highly complex process. Grammar teaching in its traditional sense, and how it is still practiced in most language classrooms around the world, is not the most effective way to become proficient and can actually delay the students in their learning process.
A heavy focus on grammar can make language learning less enjoyable for the students, as well as the teachers. Language learning is not driven by grammar, it is driven by meaning. Therefore focusing on a content-driven approach, contextualisation and making sure the learners have enough opportunities for personalisation proves to be more successful in helping students to 'learn' the grammar of a foreign language.
Grammar is important
It is helpful to be aware of the rules underlying a certain grammatical feature, but one does not need to have detailed explicit knowledge. Grammar teaching has its place in the language classroom and it is important. Studies have shown that not teaching students who are learning a foreign language about the grammatical system of the language will prevent them from being fully proficient in the language. But grammar teaching needs to serve as a means to an end, it should be used to equip a learner with the skills to properly express themselves in the language. Explicit grammar instruction in the way it is still done in language classrooms around the world, is not the most effective way.
What Does This Mean for Teachers?
Teach grammar in a more communicative way, there are two approaches that one could try to incorporate in their teaching, the PACE model (Donato and Adair-Hauk, 1992) and Processing Instruction (VanPatten, 2002). But, however one ends up teaching grammar, it is vital to be patient with one's students and give them enough time to learn and understand, to let them make mistakes and to encourage them to be creative with the language. More practical advice can be found in my published article 'MFL Minus Grammar Equals More Proficiency (And Better Exam Results?)'.