During one study of children aged between 14 months and five years, scientists recorded that each child asked an average of 107 questions per hour. One child asked three per minute!
If you're a parent who has been through this stage, this might not surprise you, but every so often a question catches us unawares - maybe it's awkward, funny, sad, or just bizarre, but we can call them all tricky questions.
To understand these questions a little more, we spoke to early years specialist Gaynor Rice, who explains that these questions are very promising for your child's language, social and emotional development.
"Children are born critical thinkers."
She also reacts to some tricky questions sent in by the Tiny Happy People Facebook audience.
Why do children ask tough questions?
Gaynor explains that while young children are brimming with curiosity of the world around them, and have just developed the language skills to pursue that curiosity, they aren't yet "bound by the conventions that adults are when it comes to asking things".
"It links to the stage of social and emotional development where we haven't really got that empathy yet. We haven't got that understanding or this idea that other people might be judging us. Children are very much in the moment."
And this lack of social understanding means children are more than happy to ask questions as and when they pop into their head, while adults are more likely to think about the reaction of the person being asked - would this question make them feel sad or awkward, or more likely to laugh at us?
"When we call it an awkward or a tricky question, that's our feeling, not the child's."
As their social and emotional development progresses - and this often coincides with them starting nursery or school and being around other children their age - they become more aware of the effect on others and less likely to ask questions in such a frank way. So make the most of it while it lasts!
How can parents respond?
Don't panic!
When faced with a tricky question out of the blue, our instinct might push us to the extremes - to try and shut down the conversation or over-explain the subject. Gaynor suggests: take a breath, think about what your child is actually asking and find a middle ground.
Gaynor compares this panic to an old joke: "[A child asks], 'Where did I come from">