Letters “k” and “w” are considered part of the Spanish alphabet but they are only used in words borrowed from other languages, such as karate, kilo, or waterpolo.
The letter “ç” (c-cedilla) was used in Old Spanish. It is still used in many languages, such as French, Portuguese and others. It is now obsolete in Spanish. It has merged with “z” and Old Spanish coraçon, cabeça, fuerça became modern corazón, cabeza, fuerza.
Another peculiar feature of the Spanish alphabet are vowels marked by acute accents (also called diacritic signs). These are not considered to be separate letters but are used in written texts for two main purposes.
The first purpose is to mark word stress if it does not follow the most common pattern (el examen - los exámenes).
The second purpose is to differentiate words that are otherwise spelled absolutely the same, for instance: tú "you" and tu "your," sólo "only" (as in "solamente") and solo "alone".
Although most of the letters are the same as in English, German and other languages using the Latin script, some of the letters have quite a different pronunciation, compared to other languages:
If your native language uses the Latin script as well, mastering the Spanish alphabet will be relatively easy as the letters are the same and many of them have very similar pronunciation. However, it is still important to study the alphabet carefully as there are some peculiarities (accents, letters like j, ñ, ll that have different pronunciation). If you master the alphabet at the very beginning of studying the language it will save you time further down the road.