The roots for this phenomenon of making up words stems from illiteracy. Granted, some slang is created with every generation based on it’s unique activities and experiences. “Pot” (new meaning for marijuana) was a newly-defined word invented by my generation, but a lot of times a word comes from ignorance, when the illiterate can’t think of the correct word and either misuses the wrong word or makes one up. In blues and jazz, this may be called “scatting,” but in literature it is called “ignorance.” Only rarely is an object, action or event so unique that a word doesn’t exist to describe it.
Sometimes a word is changed or made up for political purposes. “Homosexual” describes a perverted (look it up; the word is used correctly) sexual orientation perfectly, and it was shortened in slang to “homo.” This was taken as an insult, so in order to make homosexuality more socially acceptable and with fewer negative connotations, it was arbitrarily changed to “gay.” This is a politically-motivated change in a word’s meaning. Another is “marriage,” which formerly meant a committed relationship between a man and a woman and blessed by God, but now means who knows what. Another is “Pravda.” which is Russian for “truth” but in fact means the state-approved version of reality that may or may not be true. The modern-day word that means “Pravda” now is “Fake News.”
In short, changing words or creating words could be a inside-joke family word, as the article describes, or an expression based on ignorance, or the planned change of a word to serve the advancement of a political agenda.