Toddler Accidentally Cusses Out Dad (VIDEO)

Poor kid, he just wants to be left to vacuum his room in peace. Instead, his nosey father lays into him with question after question: "What are you doing?" "Who is your favorite Thomas the train?" "Is it Percy?"

What is this, the Spanish Inquisition? Sheesh!

This mischievous dad clearly knows what he's doing when he asks the toddler to say "vacuum" -- but that doesn't make it any less funny. Especially since the boy says it with such enthusiasm.

Believe it or not, there's a scientific reason why toddlers are unaware of the things they say. New research published in the journal Current Biology found that toddlers don't listen to their own voice like adults do.

"[Adults] subconsciously listen to vowel and consonant sounds in our speech to ensure we are producing them correctly," the study's lead author Ewen MacDonald said, according to ABC Science. "If the acoustics of our speech are slightly different from what we intended, then … we will adjust the way we speak to correct for these slight errors."

But toddlers don't notice when they say something incorrectly and don't make the same adjustments.

Of course, that doesn't mean they shouldn't keep trying. In fact, if you're curious, researchers have identified 25 words that every child should know by the time they're two. Don't worry though, "vacuum" and "percy" are not included.