Given that international auxiliary languages allow for more efficient cooperation; I think more people should consider using an easily learnable IAL, like Esperanto.
IALs would reduce the English dominance that gate-keeps software development to English persons; and hence allow more potential software developers to better develop software. The English language is mostly dominant in software development because of linguistic imperialism.
If you’re a native English speaker. If you’re not, expect to take longer to understand what an English term means (and also to deal with the English language).
Even if they understand the English term, someone might not be readily able to type an English character.
Parsing wouldn’t be any harder with different languages. There are programming languages that have been designed in different languages.
It wouldn’t be too difficult to add support for interpreting non-ASCII tokens or syntax (literally just add the ability to recognize UTF-8); in contrast to the bigger task of creating the parsing mechanism.
There’s always using the good old syntax of LISPs if the syntax gets complicated.
EDIT: Actually, Esperanto is compatible with ASCII under the H/X spelling system; so Esperanto in particular doesnt need UTF-8 support. The only change needed is to change the tokens themselves. (main() to chefo())