"When the Dutch read the alphabet out loud, they say 'ij' even if they actually write 'y'." (http://www.dutchgrammar.com/en/?n=SpellingAndPronunciation.03)
You can find the Dutch alphabet song at http://www.dutchgrammar.com/en/?n=SpellingAndPronunciation.02 (as a Canadian, I find it amusing that the Dutch call "z" "zed").
I may not be native but I did hear that phrase in English a dozens of times but I have never used it myself. To answer this question I dived into the depth of the internet and found that the phrase "normally speaking" means the ability to speak normally, therefore the answer you seek is a no and the reason I have heard is most probably due to language transfer (e.g. Dutch natives literally translating Dutch stuff into English, I have found mostly Dutch pages dealing with this problem too...). Then again it remains plausible that in some variations of English it is used. Try to use the phrase generally speaking instead, that exists for sure :)
I'm originally from the U.S. Midwest, and from what I've been told, there are a lot of "Germanisms" in their regional English--"come with" is one that comes to mind, and perhaps "normally speaking" is another one. Always fascinating to be aware of this kind of stuff in my view!
About a century ago, a significant portion of the US Midwest preferentially spoke German, particularly in the Dakotas. But when the US and Germany were at war against each other, speaking German feel out of favor in the US. Still, a lot of German influence remains, especially in the Midwest. Here's a page with some info about that: https://en.wikipedia.org/wiki/German_language_in_the_United_States
'Normally speaking' is acceptable in this situation for English as well. The phrase is used to mean the same thing as 'normaal gesproken' in this context, and would not be misunderstood in this context.
I don't think that this is a recent language transfer from Dutch to English. English and Dutch are closest to each other, so it may be that the phrase has a root in their shared past. It is also, however, possible that it was transferred during the many interactions that Dutch and English people have had over the centuries.
I am a native English speaking and saying "Ice in normally/generally speaking very cold" is 100% something we say and "normally speaking" means exactly the same thing. I have therefore reported it. Is it not more common in Dutch however to use normaal gezien? It is something I have heard my Dutch teacher use many times...
The only ones in the course are ijs and ijdel/ijdelheid (vain/vanity). But it's a common letter so there are more, like ijzer (iron), ijver (zeal/ardour), ijken (to gauge), ijlen (a delerium or to rave) and of course compound words made with the ones I just mentioned such as ijsvrij (school day off due to cold conditions), ijzererts (iron ore) or ijdelheidsverschijnselen (vanity phenomenons).
Next to that there are a number of geographical places that start with IJ (always capitalised, because they are geographical places): IJmuiden (town in North-Holland), IJzendijke (town in Zeeland), het IJ (river through/next to Amsterdam), IJburg (neighbourhood in Amsterdam).