For example, one day I had a Finnish book with me just before I went to my comedy troupe's rehearsal. After a couple of people looked at the book and suggested it (everyone's very close-knit), I jokingly stood by the door and said "Thou shalt not pass until thou can read this word aloud to me!" The word I pointed to? Seitsemänsataayhdeksän. (I must give props to the couple people who actually tried. Most people just gaped open-mouthed at the word.)
The primary reason people I asked gave for why the word seemed difficult to pronounce was that it was "so long".
But the word is actually very simple - it means seven hundred and nine. Look at the two:
Seitsemänsataayhdeksän = 22 letters.
Seven hundred and nine = 19 letters.
There are only three letters worth of difference between the two. So why should the first seem "long" if the second doesn't? It's because of the spaces, of course. There's barely a difference between the length of those two numbers when said out loud. Here's another one.
The Latin word advesperascere means, roughly, that 'it is growing dark'. It's used to indicate that evening is coming, night is falling. In my class, some of the chief complaints about Latin words was "they're so long!". This was one of those words that I've shown to people and gotten the "too long to pronounce" reaction. But let's take a look:
Advesperascere = 14 letters.
It is growing dark = 15 letters.
They're pretty much exactly the same length - in fact, the English way of saying it is slightly longer than the Latin. So when there's virtually no difference in how long it takes to say something, why is one thing considered "long" by some English speakers while the other isn't? It can't just be the spaces, can it?
But from everything I've observed, I think it can. English is a choppy language - what with our lack of verb endings and all. But we especially don't have that many compound words. In languages like Finnish, as one teacher said, you can simply "stick a bunch of words together into one and that word will mean the combination of all of them". But in English, we're so used to having our meanings separated out into their own little words, that when those spaces are removed, we see that as "long". Even when there's not really a difference in length at all.