Au (Indic)

Aryabhata used Devanagari letters for numbers, very similar to the Greek numerals, even after the invention of Indian numerals. The ौ sign was used to modify a consonant's value ×10¹⁶, but the vowel letter औ did not have an inherent value by itself.[1]

There are three different general early historic scripts - Brahmi and its variants, Kharoṣṭhī, and Tocharian, the so-called slanting Brahmi. Au was not found in the earliest forms of Brahmi, but was found in the more flowing forms the Kushana and Gupta . Like all Brahmic scripts, Tocharian Au has an accompanying vowel mark for modifying a base consonant. In Kharoṣṭhī, the only independent vowel letter is for the inherent A. All other independent vowels, including Au are indicated with vowel marks added to the letter A.

Brahmi Au

The Brahmi letter Au, is based on the letter O which was probably derived from the Aramaic Waw . That would make it related to the modern Latin F, V, U, W, Y and Greek Upsilon.[2] Several identifiable styles of writing the Brahmi Au can be found, most associated with a specific set of inscriptions from an artifact or diverse records from an historic period.[3] As the earliest and most geometric style of Brahmi, the letters found on the Edicts of Ashoka and other records from around that time are normally the reference form for Brahmi letters, but only being found in later styles, the reference form of Brahmi Au is back-formed from later styles to match the geometric writing style.

Brahmi Au historic forms

Ashoka (3rd-1st c. BCE)	Girnar (~150 BCE)	Kushana (~150-250 CE)	Gujarat (~250 CE)	Gupta (~350 CE)

Tocharian Au

The Tocharian letter is derived from the Brahmi . Unlike some of the consonants, Tocharian vowels do not have a Fremdzeichen form.

Tocharian consonants with Au vowel marks

Kau	Khau	Gau	Ghau	Cau	Chau	Jau	Jhau	Nyau	Ṭau	Ṭhau	Ḍau	Ḍhau	Ṇau
Tau	Thau	Dau	Dhau	Nau	Pau	Phau	Bau	Bhau	Mau	Yau	Rau	Lau	Vau
Śau	Ṣau	Sau	Hau

Devanagari independent Au and Au vowel sign.

Au (ओ) is a vowel of the Devanagari abugida. It ultimately arose from the Brahmi letter , after having gone through the Gupta letter . Letters that derive from it are the Gujarati letter ઔ, and the Modi letter 𑘍.

Bengali independent Au and Au vowel sign.

Au (ঔ) is a vowel of the Bengali abugida. It is derived from the Siddhaṃ letter , and is marked by the lack of horizontal head line and less geometric shape than its Devanagari counterpart, ओ.

Gujarati independent Au and Au vowel sign.

Au (ઔ) is a vowel of the Gujarati abugida. It is derived from the Devanagari Au , and ultimately the Brahmi letter .

Telugu independent vowel and vowel sign Au.

Au (ఔ) is a vowel of the Telugu abugida. It ultimately arose from the Brahmi letter . It is closely related to the Kannada letter ಔ. Like in other Indic scripts, Telugu vowels have two forms: and independent letter for word and syllable-initial vowel sounds, and a vowel sign for changing the inherent "a" of Telugu consonant letters. Vowel signs in Telugu can interact with a base consonant in one of three ways: 1) the vowel sign touches or sits adjacent to the base consonant without modifying the shape of either 2) the vowel sign sits directly above the consonant, replacing its v-shaped headline, 3) the vowel sign and consonant interact, forming a ligature.

Telugu Au vowel sign on క, ఖ, గ, ఘ & ఙ: Kau, Khau, Gau, Ghau and Ngau. Note that how the vowel sign interacts with the base consonant is dependent on the location of the headline, the absence of a headline, and the presence of a tail to attach to.

Malayalam independent vowel and vowel sign Au.

Au (ഔ) is a vowel of the Malayalam abugida. It ultimately arose from the Brahmi letter , via the Grantha letter au. Like in other Indic scripts, Malayalam vowels have two forms: an independent letter for word and syllable-initial vowel sounds, and a vowel sign for changing the inherent "a" of consonant letters. Vowel signs in Malayalam usually sit adjacent to its base consonant - below, to the left, right, or both left and right, but are always pronounced after the consonant sound.

Odia independent vowel and vowel sign Au.

Au (ଔ) is a vowel of the Odia abugida. It ultimately arose from the Brahmi letter , via the Siddhaṃ letter au. Like in other Indic scripts, Odia vowels have two forms: an independent letter for word and syllable-initial vowel sounds, and a vowel sign for changing the inherent "a" of consonant letters. Vowel signs in Odia usually sit adjacent to its base consonant - below, to the left, right, or both left and right, but are always pronounced after the consonant sound. No base consonants are altered in form when adding a vowel sign, and there are no consonant+vowel ligatures in Odia.