I was not brought up bilingual; I didn’t start learning a second language until High School. But I have become fluent in 3.
I studied French and Spanish academically and I have taught myself Portuguese without ever entering a classroom. I now teach English as a foreign language.
I know from experience that classes only get you so far. Less than 50%. If you want to be truly fluent, most of the effort needs to come from you, not from books or teachers.
This is how I did it:
1) Keep a small vocabulary book.
A small notebook you can carry with you everywhere.
Write all the new vocabulary in the book that you learn. Physically copying the words down on paper makes you twice as likely to remember them. Also write the type of word and an example of how to use it in a sentence. The more information you have about a word, the more you will remember it.
Reading the book for five minutes before you go to sleep is ideal. The book is guaranteed to be extremely boring so you will get sleepy quickly and your brain will remember the vocabulary while you sleep. Win-Win.
This is my Spanish vocab book; it’s also a good idea to write down all of the meanings of the word. Yema in Spanish can mean three different things in English!
2) Talk to your dog
Or cat, or teddy bear, in your other language. I know it sounds stupid, but it really is useful. Your mouth will get used to forming the words and your speaking will become more fluent (speed and pronunciation in particular). You’ll also become more confident; the dog can’t judge you, so you will feel better about speaking the other language.
Patrick wasn’t very interested in what I was saying to him! He fell asleep on my knee!
3) Watch TV with Subtitles
Even if you have a high level, I recommend always watching programmes with subtitles. This way, both your ears and eyes are absorbing the information, so you are twice as likely to remember it.
It’s also a good idea to watch TV with a pen and paper. Every time you see a new word you can write it down (the subtitles will tell you how to spell it). You can look the word up in the dictionary later.
TED talks are very good for students learning English. They are only 10 minutes long and have subtitles.
Do not watch TV with subtitles in your own language; your brain focuses on the written information in your own language and not on the aural information in the language you want to learn. It’s pointless.
4) Use Music
Music is the best way to expand your vocabulary quickly: people are more likely to remember words when they are sang to a rhythm than when they are spoken. I don’t know why, but it’s true. We can all remember song lyrics from years and years ago, so learning songs in another language will ensure you remember vocabulary for the rest of your life!
Find a song you like in the language you are learning and listen to it while you are doing something else (for example travelling on the bus). Listen to it three times and try to understand as much as you can.
Then, find the lyrics of the song online and listen to the song and read the lyrics at the same time. Sing along with it if you like (this helps your pronunciation). Look up any words you don’t know.
In the future when you listen to this song, you’ll understand it all and the vocabulary, pronunciation and grammar structures will be in your brain.
This is the main way I taught myself Portuguese; I downloaded Samba music and learnt the lyrics
The disadvantage to using music is that some songs do not use correct grammar and contain vocabulary that is useless (for example “ganksta slang” in rap songs). If you see a word that you are unsure about, always google it to see if it is useful to you.
5) Read the News
It is very important to see vocabulary in its “natural habitat”; to see how words are used correctly and how the language flows. Many learners often ignore the importance of reading, but it is the best way to really “get a feel” for the language.
I find reading the news more helpful than reading stories because the vocabulary and grammar structures are more useful. In stories, the vocabulary is usually more creative and romantic; not what people say in every day life.
Some newspapers can be very difficult to understand, especially broadsheets. For lower levels read magazines (Cosmo! or Hello magazine) the vocabulary is practical and the articles shorter.
6) Don’t rely on your mother tongue
It is very easy to do: when you don’t know a word, you say it in your own language instead. This is a bad habit. If you don’t know a word try to find a way to express yourself using different words that you do know.
It is also very important not to translate from your mother tongue. Many expressions just don’t work, or don’t exist and can’t be translated.
You need to focus on what you do know, not translating in your head what you want to say.
7) Never be ashamed
I know that this is easier said than done, but in my experience the students that progress quicker are the ones who do not care what others think.
Most people will try to help you communicate and will not judge you for making a mistake.
So smile, try, and don’t give up.
That’s the best advice I can give.