When learning a language a very common thing to ask, especially by people who are particularly keen to learn a language quickly, is how many words do I need to learn in order to become conversationally fluent in that language.
There is great news here! It turns out that the number of words that you actually need to learn and understand is actually very few when compared to the total number of words in a language.
First of all, notice above that i wrote conversationally fluent, not just fluent. There is a significant difference here, which I shall now explain. To be conversationally fluent in a language means that typically in your day-to-day life, you are generally able to converse with little to no problems with those around you. You are also almost always able to read the content around you in your typical day, and also have full and rich conversations. This is different from being fully fluent in a language like a native speaker would be, where you are always comfortable from a language perspective in every situation that the world may throw at you, no matter how unusual.
It is almost always enough to become conversationally fluent in a language, and therefore be completely comfortable in your day-to-day life living abroad.
Anyway, back to the number of words. The amount of words within a language varies depending on how it is classed. However, using most measurements, a language such as Spanish or English (or indeed most European languages) has approximately 100,000 unique words. This is an awful lot of words to learn.
So how many of these words do you need to learn to become comfortable in your own life situation?
In most languages, around the top 200 words together make up around 50% of all the used languages. That is incredible – Just 200 words making up around 50% of the needed words for most sentences.
Introducing the 95/5 Language Learning Rule
If you increase the number of words further to around 2500 words then you reach around 95% of conversational understanding. This means that around 5% of the 100,000 words of a language are enough for around 95% conversational understanding. Studies have shown that if you do understand around 95% of the words in a sentence then that is enough to be able to fill in the gaps and understand what is being said in the sentence.
Of course whilst some of these 2500 words are the same for everyone, there are many words within the 2500 that will vary from person to person depending on your profession, hobbies and interests, and the challenge is knowing which 2500 words you should focus on learning.
So the answer to the question of how many words do I need to know in a language to be comfortable in most situations is a relatively tiny 2500 highly targeted words.