Before literacy was generalized words were sounds. In our post-literate age words have acquired meanings from the way we try to capture store and retrieve them. They have a meta-meaning that is carried by the symbols we use to record them. Put plainly: spelling has meaning.
Before written language the only meaning of a word was in its sound.
Through has the same number of syllables, and the same number of sounds as ski. But what one acheives in three letters, the other uses seven.
(In Italian, both would have three letters.)
This is a problem for anyone who needs to use written communication. English and French are my main languages, and both are rife with words that have meta-meanings.
Show has meta-tags that imply basicness, simplicity, classroom.
Demonstrate has meta tags that imply practicality, complexity, detail, product.
Yet the the words are not synonymous. There is a nuance. To show something is to draw attention to its existance. To demonstrate something is to "show" how it works.
Compare: "Let me show you my cow."
With: "Let me demonstrate my cow."
Even so demonstrate is often selected when show is notrong; largely I suspect from a desire to avoid underselling.
I won't go into the origins of spelling and meta-meanings here; that isn't my purpose.
The two complications combine to make my job difficult. Because I write for international readers in English I sometimes find myself opting to show and tell even when demonstrate and imform would be more accurate. I often choose the words with the simplest spellings and simplest or least ambiguous meta-meanings. Frequently I choose the shortest words, since their meaning is least likely to be confused with words or groups of words in the reader's native language.
The result is plain but irregular. And rather stilted and impoverished for someone who relishes the meticulous precision with which Jonathan Meades employs his vast and varied vocabulary, and Virgil's eight page similes (sillymes) .
Nonetheless I'm going to add some posts about how to wrangle rope and brand in Plain English.