it’s easier for children to learn more languages than adults

Kids are also assumed to operate at a child's language level. So an 8-year-old speaking both English and Spanish at the 1st grade level is impressive. But a 20-year-old speaking at a 1st grade level is considered remedial.

Even then, there's a lot to be said for experience. Computers and languages alike benefit from years of exposure. A large English vocabulary will help you pick up Spanish faster. And many years of experience on an Apple will clue you into tricks a naive Windows/Linux user would never consider.

I remember my dad trying to limit my screen time by putting a password lock on the screen saver. He was shocked to discover that an eight year old figured out how to evade it by... restarting the computer. But then he enabled password on restart and got cagey when typing it in, and that slowed my Hackerman attempts down significantly.

Kids tend to learn basic things faster. But they lack the breadth of experience to recall and apply strategies and patterns they've accrued over a lifetime. So much of what we consider "smart" versus "dumb" in problem solving is just "how many times have you already seen the answer to this question applied successfully?" Figuring something out for the first time is always harder than applying the heuristic you've been using half your life.

They do have more neuroplasticity. But we have to define what that means and where this phenomenon comes from. Most just assume that younger equals better. This is not the case. You can even keep the neuroplasticity you have had as a child. One of the defining characteristics of neuroplasticity is the ability to adapt to new views. Since children have no views yet, they have no conflicting views either, causing acceptance. This is not the case with adults. But you can instrumentalize such knowledge to essentially undo your conflicting nature to increase neuroplasticity immensely. There is a cutoff and you will have a drop in potential for neuroplasticity as you age, but this is not in your child years. If you're interested, I remember reading a study of life-long meditation on alzheimers. Maybe you can find them again. This is just one technique to increase neuroplasticity. I didn't want to mention this part, as it is against common knowledge. But common knowledge is rarely correct.

Source: I have had to deal with significant loss of neural function through mental illness and have read up a lot about this topic to better myself.