Eth

Eth (Ð, ð; also spelled edh or eð) is a letter used in Old English, Icelandic, Faroese (in which it is called edd), and Elfdalian. It was also used in Scandinavia during the Middle Ages, but was subsequently replaced with dh and later d. Its use has survived in Iceland and the Faroe Islands. The capital eth resembles a D with a line through the vertical stroke. The lower case resembles an insular d with a line through the top. The lower-case letter has been adopted to represent a voiced dental fricative in the IPA.

The letter originated in Irish writing as a d with a cross-stroke added. The lowercase version has retained the curved shape of a medieval scribe's d, which d itself in general has not.

In Icelandic, ð represents a voiced dental fricative like th in English "them", but it never appears as the first letter of a word. The name of the letter is pronounced, i.e., voiceless, unless followed by a vowel. It has also been labeled an "interdental fricative".

In Faroese, ð is not assigned to any particular phoneme and appears mostly for etymological reasons; however, it does show where most of the Faroese glides are, and when the ð is before r it is, in a few words, pronounced . In the Icelandic and Faroese alphabets, ð follows d.

In Olav Jakobsen Høyem's version of Nynorsk based on Trøndersk, the ð was always silent and was introduced for etymological reasons.

In the orthography for Elfdalian, the ð represents a voiced dental fricative like th in English "them", and it follows d in the alphabet.

In Old English, ð (referred to as ðæt by the Anglo-Saxons) was used interchangeably with þ (thorn) to represent either voiced or voiceless dental fricatives. The letter ð was used throughout the Anglo-Saxon era, but gradually fell out of use in Middle English, practically disappearing altogether by 1300; þ survived longer, ultimately being replaced by the modern digraph th by about 1500.

The ð is also used by some in written Welsh to represent the letter 'dd' (the voiced dental fricative).

Lower-case eth is used as a symbol in the International Phonetic Alphabet (IPA), again for a voiced dental fricative, and in IPA usage, the name of the symbol is pronounced with the same voiced sound, as /ɛð/ (the IPA symbol for the voiceless dental fricative is θ).