While dealing with Hebrew in SK we found that it often switches to English.

Such problem happens for many skills.
We found that it's enough to add a sentence to prompts to answer in Hebrew to address it.
Unfortunately, in many cases it means we need to clone existing skills to do the customization.

I suggest introducing a generic customization, something like a variable, that can be substituted into skills to provide orders like (but not limited to) language preference.