By the time children become three, they have usually acquired many thousands of words.
Some words children have heard multiple times, so it is not surprising that they know them, other words children may hear only once, but they so retain the meaning. Some words are difficult, and the child has to struggle to say the word but still has no problem remembering its meaning Learning a foreign language may be difficult, but it is important to remember that people are born to communicate through speech. It is a gift we all have.