4 Vowel Sandhi
Sandhi means “union.” In linguistics, sandhi is about how sounds blend and unite when they are placed next to each other.
Sandhi happens in every language, but in Sanskrit there are detailed and explicit rules about how it must happen, and unlike in English, the changes in pronunciation also affect the spellings of the words.
Becoming proficient with sandhi is an absolutely essential part of being able to communicate in or understand any language. And since Sanskrit sandhi affects spelling, it is particularly important in this language.
Sandhi is not recursive. This means that if the blending of two sounds produces two sounds which could be further blended, we do not continue to blend them. This rule prevents the original grammatical form of the word from being obscured.
Coalescence of the Same Vowel
The simplest sandhi is coalescence between vowels of the same type.
When two vowels of the same type come next to each other, they become one, as the elongated version of themselves.
a + a = ā
रामेण + सह + अगच्छत् + सीता = रामेण सहागच्छत्सीता
rāmeṇa + saha + agacchat + sītā = rāmeṇa sahāgacchat sīta
[Sītā goes with Rāma.]
i + i = ī
गच्छामि + इति + वदति = गच्छामीति वदति
gacchāmi + iti + vadati = gacchāmīti vadati
[“I go,” he says.]
u + u = ū
कुरु + उत्तम = कुरूत्तम
kuru + uttama = kurūttama
[The best Kuru]
Coalescence can also occur across different vowel types, but only if the first of the two adjoining vowels is “a” or “ā”.
When a vowel comes after “a/ā” they combine to produce the guṇa vowel.
a + i = e
महा + ईश = महेश
mahā + īśa = maheśa
a + u = o
लम्ब + उदर = लम्बोदर
lamba + udara = lambodara
a + ṛ = ar
महा + ऋषि = महर्षि
mahā + ṛṣi = maharṣi
When a guṇa vowel comes after an “a/ā” they combine to produce the vṛddhi vowel.
a + e = ai
अत्र + एव = अत्रैव
atra + eva = atraiva
a + o = au
सा + ओदनं पचति = सौदनं पचति
sā + odanaṁ pacati = saudanaṁ pacati
(She cooks rice)
When a vṛddi vowel comes after an “a/ā” they also combine to produce the vṛddhi vowel, since it is not possible to further intensify the sound.
a + ai = ai
गच्छ + ऐश्वर्यम् = गच्छैश्वर्यम्
gaccha + aiśvaryam = gacchaiśvaryam
a + au = au
यच्छ + औदुम्बरम् = यच्छौदुम्बरम्
yaccha + audumbaram = yacchaudumbaram
(Give the Audumbara fruit)
Combination of other vowels.
If the adjoining vowels are dissimilar, and the first is not “a/ā” the combination changes the first vowel to its semi-vowel equivalent.
i + a = ya
आगच्छामि + अहम् = आगच्छाम्यहम्
āgacchāmi + aham = āgacchāmyaham.
u + a = va
जयतु + आर्यपुत्रः = जयत्वार्यपुत्रः
jayatu + āryaputraḥ = jayatvāryaputraḥ
(May the Āryan descendent be victorious)
ṛ + i = ri
पितृ + ईप्सितम् = पित्रीप्सितम्
pitṛ + īpsitam = pitrīpsitam
If the first vowel is a guṇa or vṛddhi vowel, it must first be devolved into its basic components. Then the same rule can be applied.
au + e = (ā+u) + e = āve
उभौ + एव = उभावेव
ubhau + eva = ubhāveva
“au” devolves into its components: “ā+u.” The “u” then mutates to its semi-vowel form, “v.”
[internal] e + a = (a+i) + a = aya
जे + अ = जय
je + a = jaya
“e” devolves to its components: “a+i.” The “i” then mutates to its semi-vowel form, “y.”
o + a = (a+u) + a = ava
भो + अ = भव
bho + a = bhava
“o” devolves to its components: “a+u.” The “u” then mutates to its semi-vowel equivalent, “v.”
In external sandhi, however, when the first vowel is ए (e) or ऐ (ai), the “i/y” component of the vowel will disappear.
e + i = (a+i) + i = (a+y) + i = a i
स्वर्गे + इन्द्रः = स्वर्ग इन्द्रः
svarge + indraḥ = svarga indraḥ
(Indra is in heaven)
The “e” in svarge devolves to “a + i.” The “i” then mutates to its semivowel equivalent, giving “ay.” Finally, the “y” disappears.
ai + a = (ā+i) + a = (ā+y) + a = ā a
तस्मै + अददात् = तस्मा अददात्
tasmai + adadāt = tasmā adadāt
The “ai” in tasmai devolves to: “ā + i.” The “i” then mutates to “y” before disappearing.
The previous rule does not operate when अ (a) follows ए (e). In this case, the अ (a) simply disappears.
e + a = e
ते + अब्रुवन् = ते ब्रुवन्
te + abruvan = te ‘bruvan
A principle to be noticed in general is that अ (a) is a very blendable sound, but ए is very difficult to blend. अ (a) therefore tends to go away easily, while ए (e) tends to persist.