My native language is Farsi which it's alphabet is very similar to Arabic. First problem is when we work on projects that need to output RTL text. We have to program LTR with RTL string. No editor or IDE can handle it. Specially command line tools. When a string contains both LTR and RTL text then it will be a headache to maintain. You never know where is the ending quotation sign.
The other fun fact is, for us non English speakers who started programming from early years of our life, some English words doesn't mean what they actually mean. For example I didn't know what `inheritance` means in real life but I was writing hierarchy in programs for a while!
I'm a native English speaker, yet there were several words I knew the computer meaning of before I knew the normal meaning. For example: icon and palette. When people used the word "icon", but didn't mean the thing you click on to start a program, I was confused.
