Irregular Webcomic! #4336

Animals like Crikey steveirwini, which is a terrestrial snail species in the family Camaenidae, also known as beer snails.

I originally wrote this strip with the sound effect in the first panel as "Knockus! Knockus!" But then I discovered that I'd already set a precedent for the sound effect of knocking in Latin. I then commented on the problem of how to write "knock knock" in Latin to my friends, and a long rambling conversation (punctuated by unrelated interwoven conversations on Martians, soup, Labyrinth, furniture, COVID-19, and pizza) ensued:

Me: Oh... is "knock knock" two copies of the noun "knock" or two copies of the verb "knock"?
GB: I would have said it was a verb form (thus 'pulso pulso' might be more appropriate). But who knows? You could use two different verbs, just to confuse things.
TM: I view it as onomatopoeia so... yeah no idea.
GB: Or 'pulsa pulsa'. I've not done enough checking.

At this point I Tweeted, and got several responses:

Me: Is "knock knock" two copies of the NOUN "knock" or two copies of the VERB "knock"? This is important for translating into Latin!
Z: It’s two copies of the onomatopoeia “knock”
Me: … so how does one decline the onomatopoeiac form in Latin…?
A: It is one copy of the verb and one copy of the noun.
O: Which is which would be decided by inflection.
MO: Try it with one of each. But the real answer is the noun is an onomatopoeia/ideophonic, from which the verb is then derived (in english* anyway)... so I recommend whichever "sounds best". * noting that the word actually derives from proto-germanic and proto-danish.
MM: I believe it's the verb, personally.
Z: You’d have to ask a Roman
AS: If it's any help: The german translation is "klopf klopf", which can only be the singular imperative form of the verb. The noun would be "klopfen".
Me: Imperative? So… it’s telling someone to knock?
AS: Yes. If in doubt, themself.
EDG: It's the sound of a person knocking twice at a door, so it's onomatopoeia. Funny thing about that is that every culture seem to come up with different words for those sounds in their language (see e.g. animal noises in different languages), so maybe the Romans had their own too!
EDG: see e.g. foreignlanguagecollective.com/say-knock-knock-35-languages/ (In Italian it's "Toc Toc", apparently. Whether that's what ancient romans said is anyone's guess though)
AC: It is an onomatopoeic noun. If it were a horse passing, “clip, clop”, that would be semantially identical but there is no relevant verb clip or clop. Likewise, one might start “Cerrrasssh” “What’s that?”
AH: Maybe they're both vocative, then. You are addressing the abstract principle of "knock".

I reported some of this back to my friends:

Me: Huh. Twitter response tells me that in German "knock knock" is "klopf klopf", which is the imperative form of the verb.
TM: sure, but that's like being surprised it's not "to knock, to knock" in English. Which actually is pretty funny
Me: Hmmm... you know, it's kind of actually imperative in English too. I mean it's not "I knock, I knock". If you just say the sentence "Knock." it's most sensibly an instruction, asking someone to knock.
IB: It has the same form as the imperative, but I am withholding judgement on whether it is the imperative until I see more evidence...
T: Evidence? What you do you expect, a rap sheet? :-)
IB: Depends on the native speaker and what they actually said. The world is full of native speakers of languages, and most of them are fairly good at the old native speaker intuition, and terrible at understanding the workings if their own languages technically.
Me: (quoting) If it's any help: The german translation is "klopf klopf", which can only be the singular imperative form of the verb. The noun would be "klopfen".
DMc: How can it be imperative if the knocking is already being done? Who is being asked to knock?
GB: I would interpret the English version as onomatopoeia rather than an imperative.
DMc: My gut feeling for the right Latin translation would be first-person present active.
IB: The imperative in German basically is just the verb stem, so i wouldn't be surprised if it occasionally appears in other contexts. But if the person is a student of the language, or has a source, I'd accept it.
DMc: Yeah I'd make the same argument for English. "Knock" is the shortest form, it just also happens to be imperative.
Me: It's almost like English and German are related...
TM: I think "klopfen" also kinda works for stomping, might also be the sound that hooves make on cobblestones etc.
Me: klipfen klopfen

I don't think we reached any particular conclusions on the best way to write "knock knock" in Latin, but it was interesting and amusing while it lasted.

Reader Kharad B. writes:

I thought I might have some additional input for you. As a native German speaker with an interest in linguistics, I've come across the concept of the Inflektiv (sadly there's no English Wikipedia article). Basically, when you construct onomatopoeic versions of words in German, it's not like you specifically use the imperative form - rather you just use the bare root of the verb, which happens to coincide with the imperative form in almost all cases. So with our "knock knock" example:

klopfen - to knock

ich klopfe - I knock

"Klopf einfach an die Tür!" - "Just knock on the door!" (imperative), but

klopf - knock (as a sound effect) uses the Inflektiv.

So, thinking German-centrically, I of course immediately thought about how to carry this line of thinking over to Latin. In Latin, pulsus is what my Latin teacher called the perfect/passive participle form (English Wiktionary calls it the supine, which I hadn't heard before), corresponding to English knocked, as in "The door was knocked on" / "porta pulsa est". (It's pulsa and not pulsus in this example because of grammatical gender agreement, but I digress.) The present tense form of the word is actually pello - I knock / pellere - to knock.* So if we construct Latin onomatopoeia like German does - by simply removing all inflective markers - "knock knock" in Latin becomes "pell pell".

* The word pulso / pulsare you were thinking of is actually the frequentative form of the verb. In Latin, you can intensify any verb by taking its perfect/passive participle and "verbing" it. Thus, pulsus becomes pulsare, which in our case would describe intense or repeated knocking on the door. Of course, from that we could also construct the onomatopoetic "puls puls".

I hope this clears up some questions and/or raises new ones :)