We notice that the words tend to fall into natural sets:

These words tend to be read as if they were regular.

His words tend to express upon topics of childhood, nature, and American life.

As a consequence of the rule, "content words" tend to have at least three letters.

Yet the words we look up tend to be archaisms.

In fact, his words tended to cut just as sharply.

Latin words tended to be literary or scholarly terms and were not very common.

The words and vocals tend toward the light, happy side.

And the two words together tend to bring me out in a cold sweat.

These extra words will tend to be added in the word boundaries of the original sentence.