One of the reasons that it's (generally) much easier to learn to read a second language than it is to understand it in speech has to do not with the words, but with the spaces in between them.
Students learning to understand spoken conversation in another language have the common complaint that "they talk so fast." They don't, really, or at least no faster than the speakers of your native language. But unfamiliarity with the lexicon of the new language makes it hard to figure out where the gaps are between adjacent words. Unless you concentrate (and sometimes even if you do), it sounds like one continuous stream of random phonemes.
As an aside, sometimes I have the same problem with English spoken with a different accent than the one I grew up with. The character of Yaz in the last three seasons of Doctor Who is from Yorkshire, and her accent -- especially when she's agitated and speaking quickly -- sometimes leaves me thinking, "Okay, what did she just say?" (That's why I usually watch with the subtitles on.) This isn't unique to accents from the UK, of course; it's why a lot of non-southerners find southern accents difficult to parse. Say to someone from Louisiana, "Jeetyet? and they'll clearly hear "Did you eat yet?"; and one of the most common greetings is "howzyamommandem?"
I'd never really considered how important the spaces between the words are until I ran into some research last week in Current Biology in a paper entitled, "Dogs Learn About Word Boundaries as Human Infants Do," that showed dogs -- perhaps unique amongst non-human animals -- are able to use some pretty complex mental calculations to figure out where the gaps are in "Do you want to play ball?" Say that phrase out loud, especially in an excited tone, and you'll notice that in the actual sounds there are minuscule gaps, or none at all, so what they're listening for can't be little bits of silence.
By looking at brain wave activity in pre-verbal infants presented with actual speech, speech using unfamiliar/rare words, and gibberish, scientists found that the neural activity spiked when syllables are spoken that almost always (in the infant's experience) occur together. An example is the phrase, "Do you want breakfast now?" The syllables /brek/ and /fǝst/ aren't used much outside of the word "breakfast," so apparently the brain is doing some complex statistical calculations to identify that as a discrete word and not adjoined to the words coming before or afterward.
What the current research finds is that dogs are doing precisely the same thing when they listen to human language.
The authors write:
To learn words, humans extract statistical regularities from speech. Multiple species use statistical learning also to process speech, but the neural underpinnings of speech segmentation in non-humans remain largely unknown. Here, we investigated computational and neural markers of speech segmentation in dogs, a phylogenetically distant mammal that efficiently navigates humans’ social and linguistic environment. Using electroencephalography (EEG), we compared event-related responses (ERPs) for artificial words previously presented in a continuous speech stream with different distributional statistics... Using fMRI, we searched for brain regions sensitive to statistical regularities in speech. Structured speech elicited lower activity in the basal ganglia, a region involved in sequence learning, and repetition enhancement in the auditory cortex. Speech segmentation in dogs, similar to that of humans, involves complex computations, engaging both domain-general and modality-specific brain areas.
My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.
Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age. She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.
River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia. (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)
If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list. It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.
[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]