Adobe PS: dieresis
Unicode: 00A8, 0308
Languages: Afrikaans, Albanian, Basque, Catalan, Dutch, English, Estonian, Finnish, French, German, Greek - (ellenika), Hungarian, Icelandic, Inari Sámi, Italian, Malagasy, Pizzonese, Skolt Sámi, Slovak, Spanish, Swedish, Turkish, Welsh
Diaeresis, Umlaut
History and examples of use
Although they take the same form and use the same character encoding, diaeresis and umlaut indicate two very different linguistic realities. Diaeresis indicates that two vowels that normally form a diphthong should be pronounced separately, as in the French naïf. Vowels carrying a diaeresis are not usually treated as separate letters for sorting. An umlaut is a modified vowel pronunciation, and languages that use the umlaut, such as German, usually treat umlauted vowels as separate letters of the alphabet.
In German, and its varieties, umlaut with ä, ö and ü replaced the original blackletter e, which had the same meaning and was placed after or above the character. Luxembourgish adds the ë. In Slovak, the umlaut is to be found with ä, in Albanian with ë, in Slovenian and Estonian with ä, ö and ü, in Hungarian with ö and ü, in Finnish and Swedish with ä and ö, in Turkish with ü, in Icelandic with ö.
Care should be taken when discussing this accent to clearly distinguish diaeresis and umlaut in use.
Notes
German typography benefits from a rich tradition of creative approach to the umlaut. For example, it could be vertically merged into the character Ü or even replaced by small e above the vowel (in German, an umlauted vowel can be written either with the accent or in combination with the letter e, i.e Lücke=Luecke).
Design
The basic form of diaeresis and umlaut are two dots. The symbol thus may be created of two dots same as the one above i, placed in the same height. Sometimes, it is visually more pleasing to scale down the dot accents. However, even the scaled down dots should be of the same shape as the dot accent. If it is circular, the dieresis dots should be the same, if it has square shape, again the dieresis dots should abide to it, etc. The distance of the dots may be fixed, in case of ï / Ï, it is advisable to narrow the gap between the dots a little. In calligraphic faces and in handwriting, umlaut commonly has the shape of two acutes. This may cause problems in Hungarian, where it could be mistaken for double acute. In Finnish handwriting, umlaut rather often takes the shape of a tilde or macron (ã/ā for ä and õ/ō for ö), which is merely a stylistic convention and makes no difference in meaning.
Although different countries appear to have local preferences about the height of the diaeresis/umlaut above lowercase letters, the best practice for international fonts is for this accent to vertically align with the dot accent and the dot of i and j.