स्वराः (Svarāḥ), are vowels of the Sanskrit alphabet. They are also known as अच् (Ac), as in the Māheśvarī-Sūtrāṇi, the vowels are given from अ (A) to च् (C). 

इउण् । ऋऌक् । एओङ् । ऐऔच् अच्

Svaras in Sanskrit are considered as Svaras according to how long they retain their sound when spoken.

If you take any Sanskrit vowel and pronounce it for a long period of time, all of the time you will hear its sound being reverberated.

Vowels can be used independently or can be mixed with a consonant. Their pronunciation will always be the same, irrespective of how they are used.

Sanskrit Vowels

There are three types of vowels:
ह्रसव-स्वराः (Hrasava-Svarāḥ), दीर्घ-स्वराः (Dīrgha-Svarāḥ) and संयुक्त-स्वराः (Saṃyukta-Svarāḥ).

ह्रस्व-स्वराः (Hrasava-Svarāḥ) are the vowels from which all other vowels are made. They are five in number and are as given below:

स्वराः (Svarāḥ) Vowels

IAST
Transliteration

a/A
i/I
u/U
ṛ/Ṛ

Type of Vowel
(According To Place of Pronunciation)

 

 

Monophthongs

दीर्घ-स्वराः (Dīrgha-Svarāḥ): 

They are four in number and are as given below: 

Note: The sounds of दीर्घ-स्वराः (Dīrgha-Svarāḥ) are pronounced twice as long as  that of ह्रसव-स्वराः (Hrasava-Svarāḥ).

स्वराः (Svarāḥ) Vowels

IAST
Transliteration

ā/Ā
ī/Ī
ū/Ū
ṝ/Ṝ

Type of Vowel
(According To Place of Pronunciation)

 

Monophthongs

संयुक्त-स्वराः (Saṃyukta-Svarāḥ):

They have been formed by combining the ह्रसव-स्वराः (Hrasava-Svarāḥ) and the दीर्घ-स्वराः (Dīrgha-Svarāḥ). They are four in number and are as given below:

स्वराः (Svarāḥ) Vowels​

IAST Transliteration

e / E
ai / Ai
o / O
au / Au

Type of Vowel (According To Place of Pronunciation)

 

Dipthongs

Combination (Of Vowels)

अ/आ + इ/ई
अ/आ + ए
अ/आ + उ/ऊ
अ/आ + उ/ऊ

Note: The sound of the letter ऐ (Ai) is pronounced twice as long as that of the letter ए (E). The sound of the letter औ (Au) is pronounced twice as long as that of the letter ओ (O).

There is another type of Vowel in Sanskrit which is not used often. It is the प्लुत-स्वराः (Pluta-Svarāḥ). They are nine in number.

These nine vowels are: अ३ (a3), इ३ (i3), उ३ (u3), ऋ३ (ṛ3), ऌ३ (ḷ3), ए३ (e3), ऐ४ (ai4), ओ३ (o3), औ४ (au4)