As a polyglot we consider a person that is able to speak multiple languages.
But what does speaking a language actually mean?
In daily life not more than 2000 – 3000 words are actually used. Educated adults however have a passive vocabulary of around 25000 – 50000 words. So what is considered as fluent?
Well, fluency basically describes “to know a language”. Meaning: Being able to use the basic vocabulary of around 2000 words in the right grammatical structure and logical context.
This is what children do. And would you not say that a 7 year old child is fluent just because it has limited vocabulary?
Speaking also excludes writing, which states that you don’t actually have to be able to write your languages to be considered a polyglot.