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.
Xmas is a common abbreviation of the word Christmas. It is sometimes pronounced / Ë É k s m É s /, but Xmas, and variants such as Xtemass, originated as handwriting abbreviations for the typical pronunciation / Ë k r Éª s m É s /. The X comes from the Greek letter Chi, which is the first letter of the Greek word Î§ÏÎ¹ÏÏÏÏ, which in English is Christ.