This process was sometimes called linkage editing and the output known as a load module. A compiler works with what are sometimes called 3GL and higher-level languages. An assembler works on programs written using a processor's assembler language.
In general, however, when between vowels (as in exactamente) the Spanish x is pronounced like the English ks sound but softer or less explosive. When it comes before another consonant (as in expediciÃ³n), it has the s sound in some regions/countries but the soft ks sound in others.
People think they're just normal, scuzzy AM stations, only a little scuzzier and using the last letter in SEX to get noticed. People ask me why they hear Spanish on them. Many, I'd say at least half, don't believe my answer, which is that XE and XF are the Mexican radio prefixes, and that they are in another country.