Fewer than you would guess. The most common 800 to 1,000 words cover the large majority of everyday conversation, and you can get through basic exchanges with even fewer. But the word count is the easy part, and it is also the wrong thing to count.
Ask how many words you need and you are already measuring the wrong thing. A conversation is not a pile of words you build into sentences on the spot. It runs on phrases. Here is the honest answer to the number, and why the number is not what holds a conversation together.
Why the number is smaller than you think
A small set of words does most of the work in any language. The same few hundred come up again and again, while the rare ones almost never do.
Function words carry a huge share of every sentence: the, is, you, want, where, this. Add a core of everyday nouns and verbs and you have covered most of what people actually say. Learn the most common 1,000 words and you will recognize a large majority of daily speech. That is why the honest number is low. You do not need tens of thousands of words to talk. You need the right few hundred.
But the number is the wrong thing to count
Knowing 1,000 words is not the same as holding a conversation. You can know every word in a sentence and still not get it out in time. A word count measures what you recognize. A conversation demands what you can produce.
Picture two learners who each "know" 1,000 words. One reaches for the words one at a time, builds the sentence as they go, and stalls halfway through. The other has those same words bundled into ready-made phrases and keeps pace. Same vocabulary, completely different result. The difference is not how many words they know. It is the shape the words are stored in.
Conversations are built from phrases, not words
Fluent speakers do not build every sentence from scratch. They reach for whole chunks they have said hundreds of times: "¿Me puede ayudar?", "no pasa nada", "¿cuánto cuesta?" Each one comes out as a single piece, not as words assembled live.
Studies of how people actually talk find that a large share of everyday speech is formulaic, made of reused phrases rather than freshly built sentences. So the better question is not how many words you know. It is how many phrases you can say without thinking. That count is the one that predicts whether you can keep a conversation going.
Which phrases actually carry a conversation
You do not need a thousand of them. A few dozen well-chosen phrases cover most of the moments you will actually be in. Greetings. Ordering. Asking for help. Directions. Prices. Asking someone to repeat themselves.
Pick the situations you know are coming and learn the handful of phrases each one needs. And learn them whole. Not "where," "is," and "bathroom" to bolt together later, but "¿Dónde está el baño?" as one unit, the way you learned "thank you" as a kid without parsing it. A phrase learned whole comes out whole.
Say them out loud until they are automatic
A phrase you have only read is not a phrase you can say. Reading trains recognition. Speaking trains production. They are different skills, and only one of them keeps up in a live conversation.
Say each phrase out loud, tied to the situation it belongs to, until it arrives on its own. That is the gap between a vocabulary list and an actual conversation. Not more words. The same small set, rehearsed out loud until you can produce them without building them.
An honest note
This is not unique to any one language, and no app makes the words come out for you. Plenty of tools will grow your vocabulary count. The lever most learners are missing is phrase-first practice they say out loud, tied to the real situations they will be in, repeated until the phrase comes before the translation does. Count the phrases you can say, not the words you can recognize, and the conversation starts to hold together.
FAQ
How many words do you need to have a conversation? Roughly the most common 800 to 1,000 words cover the majority of everyday conversation, and basic exchanges need even fewer. But knowing that many words is not the same as being able to say them in the moment. Production is a separate skill from recognition.
How many words do you need to be fluent? Broad fluency usually takes more, often in the range of 2,000 to 3,000 words and up. But fluency is less about a vocabulary total and more about how much of your speech is automatic. Someone who can produce a few hundred phrases without thinking sounds more fluent than someone who knows thousands of words but assembles each sentence slowly.
Is it better to learn words or phrases first? For speaking, phrases. Single words you assemble one at a time are slow and tend to jam under pressure. Whole phrases come out as one piece, which is what a real conversation runs on. Learn high-frequency words inside the phrases that use them, not in isolation.
How many phrases do I need to start talking? Fewer than you think. A few dozen well-chosen phrases for the situations you will actually be in is enough to start holding short conversations. Rehearse them out loud until they are automatic, then add more as you need them.
PhraseBoost is built around exactly this: phrase-first learning you practice out loud, organized by the real situations you will be in, so the words come out as whole phrases instead of one at a time. We're launching on Android first. Join the waitlist to be the first to know when it's ready.