Excel is locale dependent in a weird way. The internal model (which includes the function names) is completely locale independent and only the UI is internation

Excel is locale dependent in a weird way. The internal model (which includes the function names) is completely locale independent and only the UI is internationalized (according to OS locale) and localized (according to Excel language version). This is not a bad construction, but breaks down spectacularly when you start to use Excel as any kind of real programming or data analysis environment, because then you get to the cracks in the user-visible “API surface” where the internal/external format distinction is somewhat smeared.