My native tongue is spanish. I teach programming at the university. My strong recomendation is in the first place to use english for ANY kind of expression when programming, that means identifiers: variable names, object names, constants, comments, etc.. anything. Since the reserved words of the languare are in english too, this increments readability of the source code. Also the english words are in averiage shorter than other tongues. The other point to consider is to create an controlled vocabulary for these identifiers that means: if you use customerID to represent , well.. the ID of a general customer you reserve that word for the same purpose when writing other applications.