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.
Unlike English, Spanish has several two-letter consonants. My Spanish-English dictionary defines ch as a consonant, as in the words chato, chaleco and mucho. Other two letter consonants in Spanish are ll and rr. They could use one letter to cover, as English sometimes uses s as sh.