Ñ
Ñ, ñ (called eñe or n with a tilde) is a grapheme used in Spanish and in several other languages using the Roman alphabet to indicate the sound which in the International Phonetic Alphabet is written [ɲ], corresponding approximately to the ny in English canyon (but in other languages, ñ stands for the sound [ŋ]—like the English ng in king—or for the nasalization of a preceding vowel). The symbol is also used in several Latin-script transcriptions, such as the standard transcription of Sanskrit, Pali and related languages.
Perhaps the best known Spanish word in the English-speaking world that has the [ɲ]-sound is mañana, 'tomorrow'.
Other languages also have the sound [ɲ], but do not use the tilde (~) for it. For example, mañana in Portuguese is amanhã (where the til, as it is called in Portuguese, is modifying the a, not the n: the grapheme nh provides the [ɲ] sound). In Occitan and Vietnamese, [ɲ] is also written nh. In Catalan, ny is used, as in the local name for Catalonia, Catalunya. Italian and French use gn, as in lasagne and champagne (which has a different pronunciation from the English).
The origin of the sign ñ is a double nn abbreviated to ñ during the Middle Ages, in Spain. In the medieval use of the Roman alphabet, and in many languages—not only in Spanish—the tilde (~) was often used to represent n or m over the preceding letter in order to save space, so ñ stood for nn, õ stood for on or om, ẽ stood for en or em (e.g. diferẽcia for diferencia “difference”), etc. The phonetic value [ɲ] for ñ was favoured in the Spanish language because, in the evolution from Latin to Spanish, the Latin sequence nn (phonetically [nn], a “long n”) often ends in the Spanish sound [ɲ], for instance Latin canna > Spanish caña 'reed'.
Ñ may be considered as a letter of the alphabet on its own, in certain languages. It is the case in Spanish.