?
As far as i know Sie is for grownups, adults so to speak, or people who 'deserve' to be called Sie because they work on certain positions or were part of a royal family.

I dont know if its still valid but if there was a royal kid < 14 they had to call him Sie or sir
In dutch we used to have a similar word:

u or U if it was the first letter in a sentence:

dutch example

U ziet er stralend uit majesteit

or

In dit geval bent u verantwoordelijk als er iets verkeerd gaat tijdens deze missie.

I cant remember if we used a capital U in the mid of a sentence / phrase (whatever you call it)
in the past, nowadays most kids seem to forgot that parents and elder people should be called U or u
Nowadays most kids arent that polite anymore and they often call their parents just you ( that would be jij or je in dutch)
or in some combinations it could be: jou or jouw
Some people believe dutch is fairly easy, but don;t be fooled cause its far from it.

I believe its way easier for a person to make him or herself understandable in english then in any other language.

Of course when it comes to grammar even the english born can mess up, it all depends on how well some one is able to learn/pickup things.

I dont mean the common typoos, cause these have nothing to do if a person can or cant make him/herself understandable.
And there will always be more ways and words to phrase a question, itt all depends in which part of the country you were born (dialect)

So generally you can describe things using more words, while still telling the same, thats why they made dictionaries.

i dont try to talk german cause that would be a laugh if i did.
But dutch or any langauge for that matter are easy to learn, if someone picks it up fast, then its more like a 'gift' to the person who picks it up so easy.