Overview

The double acute accent (˝) is a diacritic sign formed by two closely spaced acute marks placed above a letter. It is found only in Latin-script writing and is most familiar as a feature of Hungarian spelling, where it distinguishes long vowel qualities. Because of its association with Hungarian it is sometimes called the hungarumlaut. The mark modifies vowels rather than consonants and is used to signal vowel length and quality in certain contexts.

Appearance and function

Visually the double acute looks like a pair of acute accents superimposed above a letter. In practice it appears above the letters O and U in Hungarian to create the distinct letters Ő, ő, Ű, ű. Its primary orthographic role is to indicate a long form of a vowel; it does not denote stress or a separate tone in Hungarian. For a general description of diacritic marks see diacritic, and for information about vowel length marking see vowel length.

Usage in Hungarian and examples

Hungarian uses the double acute only on the two front rounded vowels that have long counterparts. Examples in isolation include:

  • Ő / ő — long variant of O-like vowel (written with double acute)
  • Ű / ű — long variant of U-like vowel (written with double acute)

These letters are treated as distinct alphabetic characters in Hungarian orthography and sorting. For background on the language and orthographic practice see Hungarian orthography. The name "hungarumlaut" reflects historical comparison with German-style umlaut, but it is functionally different from a German umlaut; see umlaut for contrasts and context.

History, typographic notes and encoding

The double acute developed as a typographic and orthographic solution to represent long front rounded vowels in Hungarian. It became standardized in the 19th century as modern Hungarian spelling was codified. In digital text, Unicode provides precomposed characters for the common letters (for example U+0150/U+0151 for O with double acute and U+0170/U+0171 for U with double acute) and also supplies combining marks so the accent can be applied to other letters if needed. Many fonts include glyphs for these letters; font design and rendering affect how distinctly the two acute strokes appear above a glyph.

Practical considerations

When typing Hungarian, most operating systems and keyboard layouts include direct keys or dead-key sequences for Ő/ő and Ű/ű; input can also be produced by entering Unicode code points or HTML numeric references (for example using the relevant &#xXXXX; reference). The double acute is rare outside Hungarian; occasional adoption in linguistic transcriptions or specific orthographies uses a combining double-acute mark, but the standard national use remains Hungarian.

Distinctions and notable facts

  1. The double acute marks vowel length (and sometimes a specific vowel quality) rather than umlaut-style fronting.
  2. Only a small number of precomposed letters exist in common orthographies, principally Ő/ő and Ű/ű in Hungarian.
  3. Unicode and modern fonts support the sign, but correct display depends on font choice and text rendering.