But you don't have to speak English to use sum() to sum values. You only have to know the language of Excel, in which sum() means adding things together.

I never understood this argument. To use a function you have to look up its name anyway*, so what does it matter which language inspired the name? I wouldn't mind if sum() was known as hezrtsh() as long as it was consistently so, I could have a chance of learning it.

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* I still sometimes struggle to remember if it's average() or mean() and whether it's count() or length() -- different programming environments use different names. So even as an English speaker, I have to look up the word for each specific programming environment.