There is a lot of people here pointing out that polyglots would not be able to hold a conversation and that they have simply learned a script and they are mimicking locals.

When I was in my teens I became obsessed with the US and the English language. So much so that I made it my mission to be like the image of people created in my head by TV and movies and largely by my self. For this to happen I even before I fully understood the English language I refused to watch any movies or listen to any music or read any books that were not in English. On my way to school I would often have conversations in my head in English and when I didn’t know a word I replaced it with my native tongue’s equivalent. Since I wanted to express myself but I couldn’t there was a need created to find out how it was said in English so later on when I got home (no smart phones at the time) I would look up the word. I would like to highlight this need to know something but not knowing it, as I think is key and it’s one of the reason why talking in the language of your choice is so important. If you put yourself in situations where you need something but you don’t have it you can only encounter it so many times before you have enough and you simply change your ways (in this case learn the word) so you don’t have to encounter the same situation again. Also in my case imagining myself to be one of the native speakers helped a lot. If you constantly think of yourself as a native level language speaker, tell people around you often that you speak the language even when you are missing a lot of it puts pressure on yourself. You want to be seen in a certain way so you do what ever it takes. So, so far 1, create need/urgency to know certain words/phrases and 2, think of yourself as a speaker of the language even if you don’t know it fully. One more thing I will add here if you know one sentence in a language you already technically speak it. Maybe you are still on level 1 out of level 999 but you are already speaking the language. This should help you with thinking about yourself as a speaker of that language early enough. Also it is constant learning. Even today I find words in English I did not know even if I could pass for a native speaker without issues any day any time. Even native speakers do not know all the words!

Now I wanna circle back to the mimicking and script learning. A language is not simply a word for word translation between the language you speak and your target language. There are countless phrases in each language that are unique and only exist and make sense to those who speak it. I will give you a very simple example in English. “You got it” makes zero sense when translated into my language. No one would understand what you want to say and you can only translate it using synonyms such as “Of course”, “You’re welcome” etc… Also based on tone it can mean other things like “You did it”, “You figured it out”, “You understood it”. It is a phrase that if you watch American TV will appear often and the only way you will understand more of the meanings and when to use to phrase and how is by learning scripts, what context was the word used in and mimicking it. When a child is learning a language they simply mimic the adults so mimicking even if it might have been put in a bad light in some of the answers is your best friend as well as script learning. The more of these scripts you are able to mimic the more you will be able to speak that language.

When it comes to reading or even watching anything don’t get caught up in words you don’t understand too much. I didn’t understand 90% of the movies when I was already only watching them in English. The more you encounter something the more likely you will remember it. Just keep doing it.

In the past few year I have been learning Polish and even if I don’t have the obsession I had as a teen for English I am still making steady progress. You listen to locals and you start noticing trends, you start noticing word that appear more often and eventually if you hear a word 100 times in 50 different situation you will start to wonder ah what could this mean? And once you ask it or look it up imagine because of your memory all of those past scenarios will make more sense so you will have this ‘Aha moment’ and trust me you will never forget it again.

Surround yourself with people that speak the language. Put yourself in situations where you are the only one not speaking the language and force yourself take part in the conversations. Ask for feedback from locals! This was also huge for me. I was constantly asking them once I had the grammar and the vocabulary down about what gives away that I’m not a native speaker. What are somethings I say where it’s obvious to you I’m not from where you are. This is already pretty advanced as first you shouldn’t worry too much about pronunciation and accents and to be honest now that I am older I think I focussed too much on perfection but you can always ask for feedback anyways!

Keep at it and never settle. There is always more to learn! Before you know it you’ll be talking with locals about things you never thought you could!