Historical languages may also have used (or are now studied using) alphabets that are derived but still distinct from those of classical Latin and their modern forms (if any).
The Latin script was typically slightly altered to function as an alphabet for each different language (or other use), although the main letters are largely the same.
Some of the results, especially from just adding diacritics, were not considered distinct letters for this purpose; for example, the French é and the German ö are not listed separately in their respective alphabet sequences.
With some alphabets, some altered letters are considered distinct while others are not; for instance, in Spanish, ñ (which indicates a unique phoneme) is listed separately, while á, é, í, ó, ú, and ü (which do not; the first five of these indicate a nonstandard stress-accent placement, while the last forces the pronunciation of a normally-silent letter) are not.
Digraphs in some languages may be separately included in the collation sequence (e.g. Hungarian CS, Welsh RH).