In addition to what people have said above, I have heard of three issues of interest.
- A friend from Japan has told me that while programmers aren't at a big disadvantage, you don't see nearly as many "power users" - non-programmers who become comfortable with macros and scripting.
- If your native language is not English, you are far more likely than English speakers to confront internationalization issues from day 1. This is doubly true if you are from Asia and have multiple multi-byte encodings running around, some of which are not recognized by your regular expression engine. The ability of widely available scripting languages to handle this is improving, but still there is a fundamental complexity that English-speakers can ignore.
- One of the serious reasons that TheDamian gives for having written Lingua::Romana::Perligata is to experiment with techniques for parsing an inflected language. There is a lot of theory out there on how to parse positional languages that are vaguely English-like. But very little if you are using an inflected language like German or Hindi (or Latin, of course).
Some non-native speakers might wish to comment on some of these items...