I only know when my sons have picked up new words when they pronounce them wrongly. That means they have never heard someone say them. If they have picked up the pronounciation correctly then the only way I know is if I 'know' I have never heard them use the word before.
The other problem comes when they use a new word when I am not right there to hear it!! Then I won't ever know. It will never be documented on my weekly HE book of pride (only good things go in there) and worse, the LA will never know.
But the new words are picked up, learnt and used whether I observe the process or not. What is a home ed mum to do????? What is an LA inspector to do???????
Chuckle happily to ourselves about the mysterious and wonderful ways of growing up.