In my experience watching regular (not even necessarily elderly) people use web sites and apps, the "hamburger" menu icon is practically never understood. Even the "X" (close) icon is often overlooked, particularly if the lines are very thin (in accordance with current aesthetics): "So why don't you search for shoes now?" - "There's something blocking the page, so I'm waiting for it to disappear." (It was one of these obnoxious "Please sign up for our newsletter" modals.) I am increasingly convinced that the only icons that are more or less universally understood are Rewind, Play, Pause, and Forward (within appropriate context).
The question is, though: Unless the specific icon is reasonably well-understood or visually striking, why would you even add an icon when you already have the label? It's just more noise for the visual system to parse.
My original point, however, was that if you can't use more space for your German translation than the English word "cart" takes up, I would still rather understand the cart icon than the mentioned abbreviations. (Obviously, it would be preferable to solve the underlying issue of a fixed layout.)
I like icons for visual hierarchy and fast recognition of known functions.
only very low key ui actions like edit I tend to keep without them.
I totally agree about the hamburger and (not just) old people.
Just the other day I had to decide between two proposals with and without icons and clearly voted for the one with icons.
