Probably ‘antiestablishmentarianism’ is one of the most notorious long English words that exist. However, in general we don’t have so many long words in the English language. This is because we use the space bar to separate words. Unlike Swedish.
In the Swedish language, grammar rules allow many words that would be separated in English to be arbitrarily conjoined, making it one veeeerrry long word. This can be mind boggling for the new language learner trying to get a grip on the linguistic acrobatics of the Swedish language.
Here are some of the longest co-joined words in Swedish. Take a breath. And speak Swedish…
1) nagellacksborttagningmedel – nail polish remover
2) diskrimineringsombudsmannen – ombudsman for discrimination
3) realisationsvinstbeskattning – capital gains tax
4) hippopotomonstrosesquippedaliofobi – fear of long words!
5) blodsockerprovtagningsmaskin- blood sampling equipment
6) användervänlighetsundersökning – enquiry into user-friendliness
7) trafikavspärrningsarbetsupgifter – traffic barrier tasks
8) eurovisionsschlagerfestivalsfinalsdeltagare – eurovision finalist
9) korttidsanställdasommarlovspraktikanter – summer job workers with short term contracts
10) mindervärdighetskomplex – inferiority complex (what one gets trying to pronounce these words!)
And finally… try this one out. According to the Guiness Book of Records the longest Swedish word is nordvästersjökustartilleriflygspaningssimulatoranläggningsmaterielunderhållsuppföljningssystemdiskussionsinläggsförberedelsearbeten.
Watching the Swedes 
This is actually two word and not one.
9) korttidsanställdasommarlovspraktikanter
Should be korttidsanställda sommarlovspraktikanter.
The main problem now is the influence af english in swedish.
People tend to use english grammer for swedish word and that sucks and change the meaning.
Like mörkhåring sjuksköterska – dark haired nurse.
If you write it as mörk hårig sjuk sköterska, it means dark hairy sick nurse, not the same at all 🙂