Vowel sandhi

Also known as: svara-sandhi, ac-sandhi

Vowel sandhi is the name for sandhi changes between two adjacent vowels.

Here is a simple example of vowel sandhi:

  • सीता उदकम् इच्छति → सीतोदकम् इच्छति
    sītā udakam icchati → sītodakam icchati
    Sita drinks water.

Table of changes

Generally, there are two ways we can describe sandhi rules:

  1. The traditional approach is to study rules. This approach can be difficult at first. But over time, it helps us master all of sandhi's details.

  2. The Western approach is to arrange these changes in a table or grid. This approach is simplistic and misses many details. But it is often easier for beginners to understand.

Each approach has its strengths and weaknesses. In this lesson, we will use both. To start, here is a table that shows the basics of vowel sandhi between two words:

a/ā i/ī u/ū ṛ/ṝ e ai o au
āyavarae 'ā ao 'āva a
āa āā āa āāvā ā
eīviria iā ia iāvi i
eīa īā īa īāvī ī
oyuūrua uā ua uāvu u
oūa ūā ūa ūāvū ū
aryṛvṛa ṛā ṛa ṛāvṛ
aryṝvṝa ṝā ṝa ṝāvṝ
aiyeverea eā eaveāve e
aiyaivairaia aiā aia aiāvai ai
auyovoroa oā oa oāvo o
auyauvauraua auā aua auāvau au

To use this table, find the first sound on the top row and the second sound on the right column. The corresponding cell in the table is the result. For example, if the first sound is i or ī and the second sound is ū, then the result is .

For details, read the rules below.

Similar vowels

If the two vowels are similar, they combine and become long:

  • सीता अश्वम् इच्छति → सीताश्वम् इच्छति
    sītā aśvam icchati → sītāśvam icchati
    Sita wants a horse.

  • शबरी इषुम् इच्छति → शबरीषुम् इच्छति
    śabarī iṣum icchati → śabarīṣum icchati
    Shabari wants an arrow.

Dissimilar vowels

If the two vowels are not similar, one of three things happens.

First: if the first vowel is simple and not a or ā, it becomes a semivowel:

  • शबरी अश्वम् इच्छति → शबर्य् अश्वम् इच्छति
    śabarī aśvam icchati → śabary aśvam icchati
    Shabari wants a horse.

  • शबरी उदकम् इच्छति → शबर्य् उदकम् इच्छति
    śabarī udakam icchati → śabary udakam icchati
    Shabari wants water.

Second: if the first vowel is a or ā, the two vowels combine and become a compound vowel:

  • सीता उदकम् इच्छति → सीतोदकम् इच्छति
    sītā udakam icchati → sītodakam icchati
    Sita wants water.

But if the second vowel is , , or , it becomes a semivowel instead:

  • सीता ऋषिम् पश्यति → सीतर्षिं पश्यति
    sītā ṛṣim paśyati → sītarṣiṃ paśyati
    Sita sees a rishi.
    (Note that the result is ar, not ār.)

Third: if the first vowel is a compound vowel (e, ai, o, au), it becomes ay, āy, av, or āv, respectively:

  • ने + अ + न्ति → नयन्ति
    ne + a + nti → nayanti
    They lead.

  • भो + अ + न्ति → भवन्ति
    bho + a + nti → bhavanti
    They become.

These rules explain most of vowel sandhi. With a few more specific rules, we will have a nearly complete picture of vowel sandhi in Sanskrit.

Compound vowels at the end of a word

At the end of a word, the compound vowels -e, -ai, and -o usually make extra changes.

Let's start with -ai since it changes in a more simple way. -ai becomes when a vowel follows it. The idea is that -ai first becomes -āy, as we saw above. Then the y sound is dropped:

  • तस्यै अश्वम् ददामि → तस्या अश्वं ददामि।
    tasyai aśvam dadāmi → tasyā aśvaṃ dadāmi.
    I give her a horse.

  • तस्यै उदकम् ददामि → तस्या उदकं ददामि।
    tasyai udakam dadāmi → tasyā udakaṃ dadāmi.
    I give her water.

In these examples, note that tasyā ends with a vowel and the next word starts with a vowel. Does vowel sandhi happen again? No. tasyā does not combine further.

-e generally follows the same pattern as -ai. -e becomes -a in front of most vowels:

  • ते आम्रम् इच्छन्ति। → त आम्रम् इच्छन्ति।
    te āmram icchanti. → ta āmram icchanti.
    They want a mango.

  • ते उदकम् इच्छन्ति। → त उदकम् इच्छन्ति।
    te udakam icchanti. → ta udakam icchanti.
    They want water.

But if the second vowel is a, then -e doesn't change. Instead, the a disappears:

  • ते अश्वम् इच्छन्ति। → ते श्वम् इच्छन्ति।
    te aśvam icchanti. → te 'śvam icchanti.
    They want a horse.

This change is similar to what happens in the combination aḥ + a. a disappears often in Sanskrit:

  • रामः अश्वम् इच्छति। → रामो ऽश्वम् इच्छति।
    rāmaḥ aśvam icchati. → rāmo 'śvam icchati.
    Rama wants a horse.

-o generally follows the same pattern as -e.

Vowels that don't use sandhi

The vowels , and -e, if they are part of a word that uses the dual number, are never changed by sandhi:

  • अग्नी अपश्यम्
    agnī apaśyam
    I saw the two fires.

  • रामो बाहू उद्यच्छति
    rāmo bāhū udyacchati
    Rama raises his two arms.

  • तौ लभेते अश्वान्
    tau labhete aśvān
    The two of them obtain horses.

Verb prefixes

If a verb prefix ends with a or ā and the root starts with , the two combine to form ār instead of the usual ar:

  • उप + ऋच्छति → उपार्च्छति
    upa + ṛcchati → upārcchati
    (Someone) approaches.
    (a + becomes ār because upa is a verb prefix.)

  • सीता ऋच्छति → सीतर्च्छति
    sītā ṛcchati → sītarcchati
    Sita goes.
    (ā + becomes ar because sītā is not a verb prefix.)


There are many small details to vowel sandhi. But this lesson is a complete summary of its most common patterns. As you read more Sanskrit, you will understand vowel sandhi instinctively.

We do not recommend memorizing the rules above. But if you would like to practice these rules, you can try applying sandhi changes to the examples below:

  • सीता एव पृच्छति।
    sītā eva pṛcchati.
    Sita herself asks.

  • अश्वाः फलानि इच्छन्ति।
    aśvāḥ phalāni icchanti.
    The horses wants the fruits.

  • नरौ नगराणि आगच्छतः।
    narau nagarāṇi āgacchataḥ.
    Two men come to the city.