Now I know what it must be like for non-English speakers to have to learn English...
...because I am trying to learn Danish. If I had to rely on the sound without the text to help me out, I'd be pretty lost. It's amazing how easy it is to pick up the written language and how hard it is to pick up the spoken language.
This is sounds very interesting. Do you if the student used other methods for distorting the recordings? I assume they were of a reasonable quality (not on a cellphone in a busy street) and basically "ideal". If so, it seems to me like a poor approximation. There's no doubt that the volume plays a role in legibility but I'd vary speed of the speech and/or added different layers of noise (TV in the background at home, office sounds, coffee shop, street traffic etc.) rather than turn the volume down because they seem as more natural (and environmentally valid) to me.
I'm definitely no expert and I'm not trying to claim that Danish is hard to understand (at least not harder than others, each with its own "feature") but the described method just sounds like a very indirect approach. I suppose that the experimenter had better control over volume than ambiguous aspects like speed of the speech (I'm sure there are ways to measure it, maybe it's hard to get untrained speakers to keep some desired speed) or background noise. This would explain the chosen method. Am I totally wrong?
Just to add some background: I live in a German town where Danish is a second language. I learned some Swedish before moving here. I have listened to (but sadly not learned) Danish as a child to a certain degree.
I absolutely agree with the comic.
The vocabulary and grammar are similar. The spoken languages aren't. Danes can understand Swedes quite well, even if it sounds strange (like someone reading a foreign language literally without knowing pronunciation rules; you can at least recognize the words). The other round, not so much (unless they are from Skåne but then they arguably don't speak Swedish in the first place ;-P).
I would say it's very easy to learn English, it is the easiest language ever. I wish every language was easy like English, or not? I don't know, I am actually happy ;D I think even people who doesnt want to speak english will learn english just from being and looking around themselves..