Two dots (diacritic)

In modern computer systems using Unicode, the two-dot diacritics are almost always encoded identically, having the same code point.

The word trema (French: tréma), used in linguistics and also classical scholarship, describes the form of both the umlaut diacritic and the diaeresis rather than their function and is used in those contexts to refer to either.

It derives from the Sutterlin script, formerly used widely in German handwriting, in which the letter e is formed as two short parallel vertical lines very close together (see under Sütterlin#Characteristics).

In the International Phonetic Alphabet (IPA), a double dot above a letter is used for a centralized vowel, a situation more similar to umlaut than to diaeresis.

In Udmurt, a double dot is also used with the consonant letters ӝ [dʒ] (from ж [ʒ]), ӟ [dʑ] (from з [z] ~ [ʑ]) and ӵ [tʃ] (from ч [tɕ]).

A number of languages in Vanuatu use double dots on consonants, to represent linguolabial (or "apicolabial") phonemes in their orthography.

In Arabic the letter ẗ is used in the ISO 233 transliteration for the tāʾ marbūṭah [ة], used to mark feminine gender in nouns and adjectives.

Although the origin of the Siyame is different from that of the diaeresis sign, in modern computer systems both are represented by the same Unicode character.

The N'Ko script, used to write the Mandé languages of West Africa uses a two-dot diacritic (among others) to represent non-native sounds.

The diacritics 〮 and 〯 , known as Bangjeom (방점; 傍點), were used to mark pitch accents in Hangul for Middle Korean.

Unicode encodes a number of cases of "letter with a two dots diacritic" as precomposed characters and these are displayed below.

[7] Since version 3.2.0, Unicode also provides U+0364 ◌ͤ COMBINING LATIN SMALL LETTER E which can produce the older umlaut typography.

The subsequent (eight bit) ISO 8859-1 character encoding includes the letters ä, ë, ï, ö, ü, and their respective capital forms, as well as ÿ in lower case only, with Ÿ added in the revised edition ISO 8859-15 and Windows-1252.

If letters with double dots are not present on the keyboard, there are a number of ways to input them into a computer system.