When used as a diacritic mark, the term dot is usually reserved for the Interpunct ( · ), or to the glyphs 'combining dot above' (  ̇ ) and 'combining dot below' (  ̣ ) which may be combined with some letters of the extended Latin alphabets in use in Central European languages and Vietnamese.

  Overdot

Language scripts or transcription schemes that use the dot above a letter as a diacritical mark:

• In Arabic romanization, ġ stands for the letter ghayin.
• Traditional Irish typography, where the dot denotes lenition, and is called a ponc séimhithe or buailte "dot of lenition": ḃ ċ ḋ ḟ ġ ṁ ṗ ṡ ṫ. Alternatively, lenition may be represented by a following letter h, thus: bh ch dh fh gh mh ph sh th. In Old Irish orthography, the dot was used only for ḟ ṡ, while the following h was used for ch ph th; lenition of other letters was not indicated. Later the two systems spread to the entire set of lenitable consonants and competed with each other. Eventually the standard practice was to use the dot when writing in Gaelic script and the following h when writing in antiqua. Thus ċ and ch represent the same phonetic element in Modern Irish.
• Lithuanian: ė is pronounced as [eː], compared to ę, which is pronounced a lower [ɛː] (formerly nasalised), or e, pronounced [ɛ, ɛː].
• Maltese: ċ is used for a voiceless postalveolar affricate, ġ for a voiced postalveolar affricate, and ż for a voiced alveolar fricative.
• Old English: In modernized orthography, ċ is used for a voiceless postalveolar affricate /t͡ʃ/, ġ for a palatal approximant /j/ (probably a voiced palatal fricative /ʝ/ in the earliest texts)
• Polish: ż is used for a voiced retroflex fricative.
• The Sioux languages such as Lakota and Dakota sometimes use the dot above to indicate explosive stops.
• In Turkish, the dot above lowercase i and j (and uppercase İ) is not regarded as an independent diacritic but as an integral part of the letter. It is called a tittle.
• In the Rheinische Dokumenta phonetic writing system overdots denote a special pronunciation of r.

The overdot is also used in the Devanagari script, where it is called anusvara.

In mathematics and physics, when using Newton's notation the dot denotes the time derivative as in . However, Newton's notation is no longer standard; instead this would be written with a prime or using Leibniz's notation.

  Underdot

• In IAST and National Library at Calcutta romanization, transcribing Indic languages, a dot below a letter indicates retroflex consonants: (in the order of Indic alphabets): ṭ, ḍ, ṛ, ḷ, ṇ, ṣ, while an underdot under an m (as in ṃ) signifies an anunaasika. Very frequently (in modern transliterations of Sanskrit) an underdot is used instead of the ring (diacritic) below the vocalic r and l.

• In romanizations of Semitic languages, a dot below a consonant is used to indicate emphatic consonants. For example, ṣ represents an emphatic s.
  • Ḍ
  • Ṣ
  • Ṭ
  • Ẓ

• In Afro-Asiatic languages:
  • Ṛ

• Asturian uses Ḷḷ for western Asturian transcriptions for the voiced retroflex plosive. Asturian also uses Ḥ for the voiceless glottal fricative.
• Ḍ is used in the O'odham language to represent a voiced retroflex stop.
• Vietnamese. The nặng tone (low, glottal) is represented with a dot below the base vowel: ạ ặ ậ ẹ ệ ị ọ ộ ợ ụ ự ỵ.
• In Yoruba, the dot is used below the o, the e and the s (ẹ, ọ, ṣ): those three letters can also occur without dot as another letter.
• In Igbo, an underdot can be used on i, o, and u to make ị, ọ, and ụ. The underdot symbolizes a reduction in the vowel height.
• An underdot x̣ represents a voiceless uvular fricative in Americanist phonetic notation.
• Underdots are used in the Rheinische Dokumenta phonetic writing system to denote a voiced s and special pronunciations of r and a.

The underdot is also used in the Devanagari script, where it is called nukta.

  Encoding

In Unicode, the dot is encoded at:

• U+0307 ȧ combining dot above (HTML: ̇)

and at:

• U+0323 ạ combining dot below (HTML: ̣)

There is also:

• U+02D9 a˙ dot above (HTML: ˙)

  Technical notes

The Overdot diacritic (Unicode combining diacritic "combining dot above" U+0307  ̇ ).

Precomposed characters: Ȧ, Ḃ, Ċ, Ḋ, Ė, Ḟ, Ġ, Ḣ, İ, Ṁ, Ṅ, Ȯ, Ṗ, Ṙ, Ṡ, Ṫ, Ẇ, Ẋ, Ẏ, Ż.

  See also

• Ȧ
• Anunaasika
• Chandrabindu
• Tittle
• Turkish dotted and dotless I
• Arabic alphabet

  External links

• Diacritics Project — All you need to design a font with correct accents