Ä

Ä (lowercase ä) is a letter of the Latin script consisting of the letter A bearing two dots above, encoded in Unicode as U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS and U+00E4 LATIN SMALL LETTER A WITH DIAERESIS.¹ It is used in several European languages, including German, Swedish, Finnish, Estonian, Slovak, and Dutch, to represent a vowel sound or quality distinct from plain A.² Whether the two dots are called a diaeresis or an umlaut depends on the language and the function the mark performs.³

Encoding

Ä and ä occupy adjacent positions in the Latin-1 Supplement block, which mirrors the older ISO 8859 treatment of accented letters such as "ä" and "ö" as individual characters rather than as base letter plus combining mark.^{1 • 6} Each also has a canonical decomposition: the capital is equivalent to the sequence A followed by U+0308 COMBINING DIAERESIS, and the lowercase to a plus the same combining mark.¹ Unicode normalization makes these two representations interchangeable: text written as a base letter plus combining diaeresis and text written with the precomposed character are canonically equivalent, and normalization forms such as NFC and NFD convert between them.⁷ The combining-mark convention also resolves ambiguity in reading order: the sequence a, combining diaeresis, u unambiguously represents "äu" rather than "aü".⁶

In UTF-8, the dominant encoding of Unicode text, Ä is the two-byte sequence C384 and ä is C3A4.² For manual input on Windows the Alt code is 196, and in HTML the character can be written as the entity Ä or the numeric reference Ä.⁴

Umlaut and diaeresis

The same two dots serve two different linguistic functions, and linguists distinguish them by name. A diaeresis signals that a vowel is to be pronounced separately from an adjacent vowel, while an umlaut marks a vowel whose quality has shifted, historically through fronting.³ In English, the diaeresis appears in words such as naïve and names such as Brontë, indicating that a vowel that might otherwise be silent is sounded or that the second vowel of a pair is pronounced separately; such spellings are now often written without the mark.⁸

In German, ä is an umlaut letter. It represents a fronted, unrounded /ɛ/ sound distinct from plain a, as in Mädchen (girl), where the sound resembles the vowel of English "bed".⁴ Whether Ä is treated as a separate letter or as a modification of A differs by language, and when the character is unavailable it is conventionally transliterated as "ae".³

Separate letter in Nordic alphabets

In Swedish and Finnish, ä is a full letter of the alphabet with its own place in sorting order. The traditional Finnish alphabet taught in schools is the basic Latin alphabet with Å, Ä, and Ö added at the end, in the order A through Z followed by Å Ä Ö, and it is identical to the traditional Swedish alphabet.⁵ In Finnish, ä represents its own vowel sound, and the vowels a, o, and u stand in strict opposition to ä, ö, and y in Finnish and cannot occur in the same non-compound word, a consequence of vowel harmony.⁹

The EU character table lists Ä and ä for Dutch, Estonian, Finnish, German, Slovak, and Swedish.² In the Swedish language, both ä and ö are considered distinct letters of the alphabet, following the letter "z".⁶

Collation and processing

Sorting ä correctly requires language-specific rules rather than simple binary comparison of code points, because collation varies by language and not just by script.¹⁰ In Finnish and Swedish, ä sorts after z as an independent letter, so a word beginning with ä follows all words beginning with unmarked letters. Finnish sorting practice is governed by several national standards, including SFS 4600 for general sorting, SFS 5050 for bibliographic sorting, and SFS-EN 13710, which is based on a pan-European standard with adaptations to Finnish usage.⁵

For text processing, the canonical equivalence of Ä with A plus combining diaeresis means that two strings that look identical may be encoded differently, and programs that compare or search text typically normalize first.⁷

References

1. The Unicode Standard, Version 17.0, Latin-1 Supplement code chart (U+00C4, U+00E4)
2. Latin letters, EU Vocabularies, Publications Office of the EU
3. Ä — A with diaeresis (umlaut), Alegsa
4. Capital Letter A with Diaeresis (Ä): symbol and codes, CyberDefinitions
5. The alphabet, Handbook of Finnish, 2nd edition (Jukka Korpela)
6. Chapter 2, The Unicode Standard, Version 18.0.0 core specification
7. UAX #15: Unicode Normalization Forms
8. Diaeresis, Concise Oxford Companion to the English Language via Encyclopedia.com
9. United Nations Group of Experts on Geographical Names, Finnish alphabet
10. UTS #10: Unicode Collation Algorithm

Topic: Encyclopedia › Society and history › Languages and linguistics › Writing and notation systems › Latin script

Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026

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