[runeblaze]

I am non-native speaker and can confirm that I can't remember how many times my grammar checker complains about my uses of "softwares" and "taxons"

[fnord77]

ez rule of thumb: Can you count it directly? If not, it doesn't get pluralized. Water, code, hardware, etc. The units of measure get pluralized, though: liters of water, pieces of hardware, pages of software

Of course it is more complicated than this and it can be broken for effect ("still waters")