Default speed for recording should be normal speech
This is the way it originally was, but I guess people were complaining that it was too fast. Of course it is "too fast" when you are just learning a language. That's why there's a replay button. It should be played at normal speech speed so that people can develop an ear for the language and speech patterns and rhythms and, if necessary, then they can take the extra second to play the slow button; however, the slow button should not be the default. Repeat: natural speech should be the default and if a learner has problems, then they can click the slower, unnatural version for further help. Duolingo should not assume that everyone automatically wants or needs "further help" right away and without asking for it (which would be by clicking the slower version).
Weird, "quick"/normal audio is the default for me too. I thought the slower audio is played by default in the veeeery begining of a course. At least, that was the case with Spanish for me, but then I think the normal speech speed becomes the default fairly quickly, automatically.
Yes I totally agree, it would be really useful to train the ear if you first heard the normal speed, but had the option to slow it down if you needed. The slow version is also quite hard to understand sometimes due to connected speech changing the pronunciation of certain words. (I am learning French and words are often pronounced differently when in a phrase or alone)