Danish is spoken at a much faster rate than other Scandinavian languages

Here's an article in Norwegian from two months ago showing a comparison between Swedish and Danish carried out by researchers from the Netherlands. Danish is often said to be the hardest to understand of the three, and it turns out that one of the reasons for that is that it is spoken 25% faster than Swedish, or up to 40% faster for single words. This means that Swedish speakers will say three words per second on average while Danes manage to fit four in.

One example is the word teachers - lærere. In Swedish this is pronounced with three syllables - læ-ra-re, but in Danish it's only two - lææ-åå.

Norwegian wasn't included in the study but Norwegian is the easiest language for Scandinavians to understand, so if anything it should be either the same or slower than Swedish.

The other interesting point the article makes is that Danish children also find it harder to learn their native tongue compared to other children in Scandinavia, although once they learn it the other ones are quite easy to understand whereas those growing up with Swedish (and certainly Norwegian) aren't used to the speed at which Danish is spoken and thus have more problems understanding it.