If you search for tips to improve your <whatever language>, you may find suggestions like “Watch films/videos/Netflix series”. It is undeniable that watching movies is an easy way to improve your language skill. However, if you calculate the time and effort you put in, the result may surprise you. The truth is that watching movies/videos is not an efficient way to learn a language.

What?! How is this possible? I have friends who learn Japanese just by watching animes. I encounter opinions that it is entirely possible. But before we go further to the point, let’s have a brief overview on some scientific facts.

So why exactly is watching movies/videos effective?

Hey, didn’t you just say it is an inefficient way of learning? Yes, but generally and sarcastically, this ineffective method outperforms most traditional ways of learning, such as taking language courses at schools. And why? Before finding answers to the question, let’s first take a look at three important phases of memorizing. The steps are: encoding, storage, and recall.

Encoding is an attempt to transform newly learned information into a form that your brain can understand in order to increase the chances of remembering it. It is also the most important part of forming long-term memories.

Now, let’s recall how vocabulary is learned in school? You repeat a word over and over again hoping it will stick in your memory, right? Yes, and that is exactly why it doesn’t work. The problem is that the whole process doesn’t involve encoding at all. Lack of encoding leads to so-called pointless repetition. Even if you don’t know anything about neuroscience, you know this method doesn’t work well.

In contrast, when watching a movie, the brain unconsciously performs many activities that are beneficial for the formation of long-term memory. These activities include:

1. encoding: movies contain images, sound effects, etc. A movie somehow secretly encodes new vocabulary into these forms to make it easier for you to remember. (The movie does the encoding for you).
2. spaced repetition: studies have shown that spaced repetition is superior to focus repetition. Watching movies is a form of effective repetition as the repetition is “spaced out”. Frequently used words and phrases will be repeated at different times.
3. Exposure to context: Common words, expressions and phrases appear in different contexts, indicating that you are exposed to more of the language.
4. Emotional saliency: Even without referring to scientific research, it is no doubt that things that are emotionally important to us are more likely to be remembered. Generally, movies have rich amount of materials that make many things emotionally salient.

As you can see, there are hidden scientific facts that make watching movies so powerful. But…

Why isn’t it efficient enough?

Let’s do some simple math together. How many words can you learn by watching a 20-minute video? The answer may surprise you; in that time, a person can probably learn about three new words. So what would you do to learn new words? Do you write them down in a notebook? Do you consult the dictionary? Do you also spend some time trying to memorize these words? If your answer is yes to any of these questions, then how much time do you spend for learning these three words? Let’s assume that you have a superb memory, meaning you never forget a word after enough repetitions in just ten minutes and you need only 10 minutes to recite these words. Under this perfect assumption of 30 minutes a day, you would learn three new words a day, or about 1,000 words a year. It would then take a staggering five years to reach basic fluency. (about 5,000 words). Life is too short to learn at this pace.

So how can we turn this around? This is another big question to answer. I would like to offer a brief conclusion and some suggestions here.

1. Learning a language requires some basic understanding on how memories are formed.
2. Encode anything you wanna learn in a way that you can remember, using pictures or sounds will help.
3. Use spaced repetition programs such as ANKI.
4. If you wanna learn as fast as possible, you should focus on vocabulary acquisition. Aim for 10,000+ words if you really wish to be fluent. (most language learners know way less than this amount and that could be a problem)
5. Watching movies won’t hurt, but it’s just not as effective as you might think.