I was once again distracted by something ridiculous in the HNQ sidebar: Scientific applications of the tikzducks.

One answer states that

It is possible to form a grammatical English sentence of length n, using only the words "duck" and "ducks", for all values of n.

I'm having a hard time understanding the sentences of length 4 and above. What exactly do they mean and why are they grammatically correct? I tried replacing part of the sentence tree with something else, such as "cows moo", but the resulting sentence "Ducks cows moo duck" does not seem to have any meaning.


1 Answer 1


Let's agree that hunters hunt ducks, and that ducks, even ducks that are hunted by hunters, eat. So:

"Ducks that hunters hunt eat."

Let's also agree that alligators will eat ducks if they have the chance. So:

"Ducks that alligators eat eat."

Now, what if there were cannibalistic ducks? Well, even the ducks that those ducks eat eat:

"Ducks that ducks eat eat."

In sentences with restrictive relative clauses like these, "that" can be omitted:

"Ducks ducks eat eat."

Now, suppose that ducks not only eat, but they also duck. Then one can also say:

"Ducks that ducks eat duck."


"Ducks ducks eat duck."

Finally, suppose that ducks not only eat and duck, but they also duck other ducks. Then:

"Ducks that ducks duck duck."


"Ducks ducks duck duck."

Wikipedia has an article on this sort of thing, involving buffalo from Buffalo that buffalo other buffalo from Buffalo: https://en.wikipedia.org/wiki/Buffalo_buffalo_Buffalo_buffalo_buffalo_buffalo_Buffalo_buffalo.
Your attempt with "moo" doesn't work because the concept of cows mooing ducks doesn't work--"moo" doesn't take a direct object. It might have been a bit clearer if you'd gone with "Ducks cows milk duck" if cows were in the habit of milking ducks.

  • 1
    It's worth noting that this is a self-embedded sentence. While sentences of n>5 words that are just "duck(s)" are technically grammatical, they are impossible to understand by humans.
    – Laurel
    Commented Mar 26, 2018 at 17:31
  • @Laurel: That was also an interesting read, thanks for the reference.
    – JohnEye
    Commented Mar 27, 2018 at 10:24

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