You have multiple layers with different idiom.
Use this !!!
Hide all the layer except one , run the spell check , Ideally it will run the spell check on all the layer but because they are hidden you will not see it .
Correct the text in that layer , hide it and unhide other layer and repeat the steps for all the layers one by one.
The best I can think of without using any third party script or plugin as I dont know any.
Thank you for your suggestion, unfortunately I've already tried this strategy.
I don't understand why but the spell check runs also on the hidden layers.
In the previous version of Indesign I haven't this problem.
The only complicated (and uncomfortable) solution that I found it is to duplicate the doc and cancel all the layers except one language. When I find an error in the cloned doc I have to correct in source file.
In my opinion it's a bug of Indesign. In the spell check it'd be useful an option relating the layers.
Thanks in any case.
If ALL text on every of your layers have the SAME language assigned to them, it could be scripted:
1. For every hidden layer, store its language.
2. Set all of the text on that layer to [No Language]. That way, the spell checker will ignore it.
3. Do your spell check.
4. Restore the original languages on hidden layers.
This method will ONLY work if all of the text is actually set to the same language (yeah I know, I said it at the start; but it's a crucial point!)
Use dynamic spelling, it might be quicker considering the layers.