Joker asks participants to write a sentence using just one word.

Compare results. (No need to split hairs over the definition of a sentence, the purpose is to play with language.)

Joker then asks for two-word sentences.

Compare results.

And so on, one, two three, five, ten words, then jump to twenty, fifty, one hundred-word sentences.

Have people find examples of each, feeling free to use poetry, lyrics, any text.

Play the same game additively, start with one word, add another, and another.
Start with two words and ask people to write into them, adding words to build increasingly long sentences.

This works very well as an improv dialogue game in which pairs have to make dialogues first of one word each, then two words, then three, five, ten and twenty.