Have you considered what happens if, when talking to your kids...
…you use “saturation of color” instead of “how dark the color is” (dark is not the right term, but one we use often to mean intensity of color)?
…or “vehicle” instead of “car”?
…or “patella” instead of “kneecap”?
What happens? Nothing weird. Kids can learn the big words just as easy as the little words.
We humans, especially women, are hard-wired to use “motherese”—the higher pitched, slower talk that repeats and rhymes. This is excellent and necessary for teaching language to a child. So necessary, in fact, that the Lord made this trait universal. Even males will automatically fall into a version of this when talking to a baby or small animal.
However, at some point the infant/toddler has grasped the concept of language, built the framework of how his language sounds, its patterns and rhythms. Even if the child doesn’t know how to actually speak words, they will babble in fairly recognizable patterns for their native language.
Then it’s our job to start building their vocabulary. That’s when we often have a tendency to stick with easy words and shorthand.
The thing is that “patella” is just as easy to learn as “kneecap” to a child. If we use big words with children, they use big words too (It’s so adorable to hear a 4 year old say “That’s not a tractor, that’s an excavator!”).
There’s nothing wrong with using smaller words, of course. Kneecap is perfectly acceptable (though using “darkness” for “saturation” makes artists cringe).
However, there are a few benefits for using large words with small kids:
It teaches children complexity
It facilitates reading higher level materials later
STEM and STEAM concepts are more easily understood and the children are automatically more comfortable when encountering a word in Physics 1 that they have used since they were 7
Broad and advanced language helps forestall some naysaying on the part of others if we decide to homeschool or if our child is not following the beaten path.
So consider just using big words! If your child says “OOOO! A butterfly!” your speedy google can help you sound brilliant when you say “Butterflies are in the order of insects called Lepidoptera. Can you say Lepidoptera?” Even if neither of you can say it at first, just giggle then google :D. You can find the pronunciation in a dictionary app, AND your child will have just learned a little STEM (and if anyone is doubting your ability to teach, you can simply say “Son, what did we learn about butterflies today?” ;) )