Morph

Morph lined up two rows of endings.

"Row one," it said, "changes what kind of word the root is. -or turns act into a person: actor. -ive turns it into a describer: active. -ion turns it into a thing: action. These are derivational coats — they derive a new word out of the old root. After I put one on, the word has a new job, a new part of speech, sometimes a new spot in the dictionary entirely."

It shook out the second row.

"Row two only tunes the grammar — it keeps the job exactly the same. Act, acts, acted, acting. Every one of those is still a doing-word. -s just says 'happening now, to one person.' -ed says 'already happened.' -ing says 'happening in an ongoing way.' The job never changed — it's still an action-word. These are inflectional coats. They don't build a new word; they adjust the one you've got."

The young creatures stared. Actor and acted had always looked like the same kind of change. They weren't. One built a new word. One only tuned the old one.

"Why does the difference matter?" a young creature asked. "They're both just endings."

"Because it tells you what a word is, instantly," Morph said. "See a derivational ending — -tion, -ment, -ness, -er, -ful, -ize, -ly — and you know the root just changed jobs: it became a thing, or a describer, or a doer. See an inflectional ending — English only has a handful: -s, -es, -ed, -ing, -er, -est, -'s — and you know the job stayed the same, the grammar just shifted. When you meet a monster word, the ending is the first thing that tells you its part of speech. Nationalization ends in -tion — that's derivational, so no matter how scary the middle is, the whole word is a thing, a noun. You knew that before you understood a single other piece."

Then Morph turned the trick on its own name, which delighted it endlessly.

"My root is morph — it means shape or form," it said. "Watch me do to myself what I do to everything else. Morph — to change shape, a doing-word. Add the -ology coat: morphology — the study of forms, a thing. Add a describing coat: amorphous — without form. Add another: polymorphous — many forms. And the grandest one — metamorphosis — a complete change of form, the word for a caterpillar becoming a butterfly." It spread its shimmering arms. "I am the creature whose name means shape-change, doing shape-change to its own name. Every coat a different job, every job the same root: form."