The modern German alphabet consists of the twenty-six letters of the ISO basic Latin alphabet plus four extra letters placed at the end:
German uses letter-diacritic combinations (Ä/ä, Ö/ö, Ü/ü) using the umlaut and one ligature (ẞ/ß (called eszett (sz) or scharfes S, sharp s)), but they do not constitute distinct letters in the alphabet.
Ü (lowercase ü) is a Latin script character composed of the letter U and the diaeresis diacritical mark. In some alphabets such as those of a number of Romance languages or Guarani it denotes an instance of regular U to be construed in isolation from adjacent characters with which it would usually form a larger unit; other alphabets like the Azerbaijani, Estonian, German, Hungarian and Turkish ones treat it as a letter in its own right. In those cases it typically represents a close front rounded vowel [y] .
Although not a part of their alphabet, Ü also appears in languages such as Finnish and Swedish when retained in foreign proper names like München ("Munich"). A small number of Dutch and Afrikaans words employ the character to mark vowel hiatus (e.g. reünie /reːyˈni/ ("reunion"), a loanword marked with diaeresis to suppress the native reading of eu as a digraph pronounced /øː/).
The history of mathematical notation covers the introduction, development, and cultural diffusion of mathematical symbols and the conflicts between notational methods that arise during a notation's move to popularity or obsolescence. Mathematical notation comprises the symbols used to write mathematical equations and formulas. Notation generally implies a set of well-defined representations of quantities and symbols operators. The history includes Hindu–Arabic numerals, letters from the Roman, Greek, Hebrew, and German alphabets, and a variety of symbols invented by mathematicians over the past several centuries.
The historical development of mathematical notation can be divided into three stages:
The letter Å (å in lower case) represents various (although often similar) sounds in several languages. It is a separate letter in Danish, Swedish, Norwegian, Finnish, North Frisian, Low Saxon, Transylvanian Saxon, Walloon, Rotuman, Chamorro, Lule Sami, Pite Sami, Skolt Sami, Southern Sami, Ume Sami, Pamirian languages, and Greenlandic alphabets. Additionally, it is part of the alphabets used for some Alemannic and Austro-Bavarian dialects of German.
Though Å is derived from A by adding an overring, it is typically considered a separate letter. It developed as a form of semi-ligature of an A with a smaller o above it to denote a rounding of the long /a/ in Old Danish.
In Unicode, a script is a collection of letters and other written signs used to represent textual information in one or more writing systems. Some scripts support only one writing system and language, for example, Armenian. Other scripts support many different writing systems; for example, the Latin script supports English, French, German, Italian, Vietnamese, Latin itself, and several other languages. Some languages make use of multiple alternate writing systems and thus also use several scripts; for example, in Turkish, the Arabic script was used before the 20th century but transitioned to Latin in the early part of the 20th century. More or less complementary to scripts are symbols and Unicode control characters.
The unified diacritical characters and unified punctuation characters frequently have the "common" or "inherited" script property. However, the individual scripts often have their own punctuation and diacritics, so that many scripts include not only letters but also diacritic and other marks, punctuation, numerals and even their own idiosyncratic symbols and space characters.