Diaeresis (diacritic) in the context of "Overstriking"

A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek διακριτικός (diakritikós, "distinguishing"), from διακρίνω (diakrínō, "to distinguish"). The word diacritic is a noun, though it is sometimes used in an attributive sense, whereas diacritical is only an adjective. Some diacritics, such as the acute ⟨ó⟩, grave ⟨ò⟩, and circumflex ⟨ô⟩ (all shown above an 'o'), are often called accents. Diacritics may appear above or below a letter or in some other position such as within the letter or between two letters.

The main use of diacritics in Latin script is to change the sound-values of the letters to which they are added. Historically, English has used the diaeresis diacritic to indicate the correct pronunciation of ambiguous words, such as "coöperate", without which the <oo> letter sequence could be misinterpreted to be pronounced /ˈkuːpəreɪt/. Other examples are the acute and grave accents, which can indicate that a vowel is to be pronounced differently than is normal in that position, for example not reduced to /ə/ or silent as in the case of the two uses of the letter e in the noun résumé (as opposed to the verb resume) and the help sometimes provided in the pronunciation of some words such as doggèd, learnèd, blessèd, and especially words pronounced differently than normal in poetry (for example movèd, breathèd).

Tau (/ˈtaʊ, ˈtɔː, ˈtɒ/ ; uppercase Τ, lowercase τ or τ; Greek: ταυ [taf]) is the nineteenth letter of the Greek alphabet, representing the voiceless dental or alveolar plosive IPA: [t]. In the system of Greek numerals, it has a value of 300.

The name in English is pronounced /taʊ/ or /tɔː/, but in Greek it is [taf]. This is because the pronunciation of the combination of Greek letters αυ can have the pronunciation of either [ai], [av] or [af], depending on what follows and if a diaeresis is present on the second vowel (see Greek orthography).

A second language (L2) is a language spoken in addition to one's first language (L1). A second language may be a neighbouring language, another language of the speaker's home country, or a foreign language.

A speaker's dominant language, which is the language a speaker uses most or is most comfortable with, is not necessarily the speaker's first language. For example, the Canadian census defines first language for its purposes as "What is the language that this person first learned at home in childhood and still understands?", recognizing that for some, the earliest language may be lost, a process known as language attrition. This can happen when young children start school or move to a new language environment.

Ä (lowercase ä) is a character that represents either a letter from several extended Latin alphabets, or the letter A with an umlaut mark or diaeresis. It is used mainly in Northern European and Central Asian languages. In the International Phonetic Alphabet, it is sometimes used to represent the open central unrounded vowel.

Isoetes, commonly known as the quillworts, is a genus of lycopod. It is the only living genus in the family Isoetaceae and order Isoetales. As of 2016, there were about 200 recognized species, with a cosmopolitan distribution mostly in aquatic habitats but with the individual species often scarce to rare. Species virtually identical to modern quillworts have existed since the Jurassic epoch, though the timing of the origin of modern Isoetes is subject to considerable uncertainty.

The name of the genus may also be spelled Isoëtes. The diaeresis (two dots over the e) indicates that the o and the e are to be pronounced in two distinct syllables. Including this in print is optional; either spelling (Isoetes or Isoëtes) is correct.

Umlaut (/ˈʊmlaʊt/; UUM-lout) is a name for the two dots diacritical mark (◌̈) as used to indicate in writing (as part of the letters ⟨ä⟩, ⟨ö⟩, and ⟨ü⟩) the result of the historical sound shift due to which former back vowels are now pronounced as front vowels (for example [a], [ɔ], and [ʊ] as [ɛ], [œ], and [ʏ]). (The term Germanic umlaut is also used for the underlying historical sound shift process.)

In its contemporary printed form, the mark consists of two dots placed over the letter to represent the changed vowel sound. In some Romance and other languages, the diaeresis diacritic has the same appearance but a different function.

Ö, or ö, is a character that represents either a letter from several extended Latin alphabets, or the letter "o" modified with an umlaut or diaeresis. Ö, or ö, is a variant of the letter O. In many languages, the letter "ö", or the "o" modified with an umlaut, is used to denote the close- or open-mid front rounded vowels [ø] or [œ] ; compare the vowel in "girl", which in these languages phonetically could be written: /görl/. In languages without such vowels, the character is known as an "o with diaeresis" and denotes a syllable break, wherein its pronunciation remains an unmodified [o].