What's the hardest word to pronounce in your language?

превысокомногорассмотрительствующий.
Russian

"viskelær can be difficult meaning an eraser

Bringebærsyltetøy raspberryjam
Kjøttkakemiddag, meatloaf dinner
loads of food words can be very complicated

biangbiang面 (A kind of delicious noodles)
↑
The Chinese character is too complex to show.

Haar - a wonderful word for scrabble but not well known?

Loch of course is a shibboleth and marks you out as Scottish or English

A German word: "Eierschalensollbruchstellenverursacher",
something that you can use to open your breakfast egg perfectly.

Pneumonoultramicroscopicsilicovolcanoconiosis

One of the difficult languages to learn or pronounce a word is German, but I would like to learn

The classic: Chuchichäschtli✨

defribiliering (swedish)

Colonel… it is spoken like ‘Kernel’

"Rinder­kennzeichnungs- und Rindfleisch­etikettierungs­überwachungs­aufgaben­übertragungs­gesetz"

Not a joke - this monster was created by German officials to name a law. Well, yeah... who else can come up with such an idea? 😃

You need an explanation? Well, then have a look at this (including a Listening-Link):
https://en.wikipedia.org/wiki/Rinderkennzeichnungs-_und_Rindfleischetikettierungs%C3%BCberwachungsaufgaben%C3%BCbertragungsgesetz

"Otorrinolaringologia" which is the spanish word for the Health specialty for the Ears, Nose and Throat/ENT, which is way easier to refer to

Защищающийся. Zashchishchayushchijsya

I'll go with "otorrinolaringólogo", "paralelepípedo" and "esternocleidomastoideo".

(Until recently I didn't know how to say "frambuesa") 💀

For everybody from out of Switzerland its CHUCHICHÄSCHTLI.

Worcestershire and Colonel

The classic: Chuchichäschtli✨