The letter Ñ in Spanish
Why is there a letter "ñ" in Spanish. The answer is actually quite simple. Back in the 12th century books or anything written had to be copied by hand. Usually this was done by monks.
As you may know a great many of Spanish words (about 80%) are derived from Latin. In addition most of the books that the monks were copying were in Latin. Whenever they would encounter a word that had two letters repeated they would put an ~ (called a tilde) over only one letter. This would indicate that there was actually two letters and the word should be pronounced as such. They would of course omit the second letter. Therefore a word that had a double "aa" would be written as ã and a word that had a double "nn" would be written as ñ.
In about the 14th century they only continued use the tilde mark (~) on words that had a double nn. They stopped using it for all other double letter combinations. However they continued using it not only for double nn words (such as año which means year in Spanish and it derived from the latin word annus), but also for words that have a double nn sound.
Therefore in Spanish they write señal and campaña, that are English cognates, using the ñ where English uses "gn," such as in "signal" and "campaign," respectively.
By the way if you wish to type the letter ñ or Ñ this is how you do it on the computer.
To type ñ you would hold down the "alt" key and type the numbers 164. Then release the "alt" key.
To type Ñ you would hold down the "alt" key and type the numbers 165. Then release the "alt" key.