I just came in here to say that the 2000s version of Pingu sucked ass and they could have found someone better than whoever they did to do Pingu's voice properly.
I was being facetious, however how one would spell something in what isn't their language can be difficult. Look at /r/boneappletea for examples.
Once you showed me a better way of describing the sound it makes instant sense. Even though by thinking about it I can almost hear the sound, it's rather hard finding the correct way to describe it in English (which isn't my native language)
Interesting. English isn't my native language either, but I do speak and write at a native level due to a few factors, so that might be the difference.