Public navigation menu entry is 'automagically' translated

On my Polish localized Omeka (2.1.4) i tried to modify public menu entries in Navigation settings. All works Fine but the strange thing is, that when I create an entry with a name like 'Search' or 'Item' (or any other translateble name), this is shown in the main navigation translated to Polish - which is not desirable in the particular use case. I'd like to have the public navigation menu exactly what I entered in the navigation settings.
I use the public_nav_main() function in my public theme. I also tried pass the navigation menu entries manually as an array, using the nav() function but the effect is the same.