Internal Consonant Sandhi

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• Terms
• General Rules
• Aspirated Letters
• Letters from cavarga
• Retroflex letters
• Final n and m
• Final s
• Special Rules
• Charts

This page covers the rules of internal consonant sandhi. Internal consonant sandhi acts within a single word. Any rule in which the first letter is a consonant is considered a consonant sandhi rule. Some of the rules have charts, which you can see at the bottom of the page.

As far as I am aware, this page contains every rule of internal consonant sandhi. Pre-Classical works don't always conform to these rules.

General Rules

Internal and external consonant sandhi

The internal consonant sandhi rules and external consonant sandhi rules have many rules in common. The best way to think about the rules on this page is as "exceptions" to the normal external consonant sandhi rules. So, when you apply consonant sandhi, you should first check for the exceptions mentioned on this page; and if there aren't any that apply, you should use the external consonant sandhi rules.

No sandhi near certain letters

When the second letter letter is a vowel, a nasal, or a semivowel, no sandhi change of any kind will occur, with only a few exceptions.

Here are some examples of the general rule:

• वच् + अन्ति → वचन्ति

  vac + anti → vacanti

• वच् + मि → वच्मि

  vac + mi → vacmi

• वाच् + य → वाच्य

  vāc + ya → vācya

• वच् + ति → वक्ति

  vac + ti → vakti

Assume that all rules follow this principle. Those that do not will be clearly labeled.

Aspirated Letters

These rules apply to the first letter.

General Rule

Aspirated letters become unaspirated.

• रुन्ध् + ध्वे → रुन्द्ध्वे

  rundh + dhve → runddhve

Exceptions for -h

h is treated like gh when either of these things is true:

• The second letter is s
• The h both ends a root that starts with d and is in front of t, th, or dh.

• लेह् + सि → लेक् + सि → लेक्षि

  leh + si → lek + si → lekṣi

• दह् + त → दग्ध

  dah + ta → dagdha

• दिह् + ध्वे → दिग्ध्वे

  dih + dhve → digdhve

In other roots, h does all three of these peculiar things:

• changes t, th, and dh — if they follow the h — into ḍh
• lengthens the vowel in front of it, if possible
• disappears

• मुह् + त → मूढ

  muh + ta → mūḍha

• लिह् + त → लीढ

  lih + ta → līḍha

• ऊह् + त → ऊढ

  ūh + ta → ūḍha

Four exceptions are snih, muh, nah and dṛh.

• नह् + त → नद्ध

  nah + ta → naddha

• दृह् + त → दृढ

  dṛh + ta → dṛḍha

Moving the aspirate backward

A piece's first letter will become aspirated if all of these things are true:

• The piece starts with g, d, or b.
• The piece ends with a voiced aspirate consonant (including h).
• The aspirated sound at the end has been removed due to sandhi.
• The first sound after the piece is bh, s, or dhv.

The fourth requirement is for internal sandhi only. The other three are the same as in external consonant sandhi.

• अ + बुध् + ध्वम् → अभुद्ध्वम्

  a + budh + dhvam → abhuddhvam

Moving the aspirate forward

t- and th-, when they are the second letter, become dh-.

• बुध् + त → बुद्ध

  budh + ta → buddha

• रुन्ध् + थः → रुन्द्धः

  rundh + thaḥ → runddhaḥ

• दुह् + त → दुग्ध

  duh + ta → dugdha

One exception to this rule is the root dhā, which becomes dhat in this situation.

Letters from cavarga

Final j

By the external sandhi rules, c always reduces to k. But j is more irregular. It usually becomes k, but it can also become ṭ or ṣ.

• युज् + त → युक्त

  yuj + ta → yukta

• राज् + त्र → राष्ट्र

  rāj + tra → rāṣṭra

• मृज् + हि → मृड्ढि

  mṛj + hi → mṛḍḍhi

Final ś

A final ś changes in these ways:

• In front of t or th, it becomes ṣ and shifts the letter that follows it to ṭavarga.
• In front of the s of a verb suffix, it becomes k.

• द्रश् + स्य + सि → द्रक्ष्यसि

  draś + sya + si → drakṣyasi

prach

prach is treated like praś. In external sandhi and ātmanepada, it becomes praṭ.

• पृछ् + त → पृष् + त → पृष्ट

  pṛch + ta → pṛṣ + ta → pṛṣṭa

Changing n- to ñ-

Final c and j change n- to ñ-.

• याच् + ना → याच्ञ

  yāc + nā → yācñā

• यज् + न → यज्ञ

  yaj + na → yajña

Retroflex letters

A retroflex letter, if followed by a tavarga letter, shifts it to ṭavarga.

• इष् + त → इष्ट

  iṣ + ta → iṣṭa

• विश् + त → विष् + त → विष्ट

  viś + ta → viṣ + ta → viṣṭa

ṣ becomes k when followed by s.

• द्वेष् + सि → द्वेक्षि

  dveṣ + si → dvekṣi

Final n and m

Final n becomes the anusvāra if both of these things are true:

• The n is the last letter of a verb root
• The initial letter is s

• जिघान् + स + ति → जिघांसति

  jighān + sa + ti → jighāṃsati

• मीमान् + स + ति → मीमांसति

  mīmān + sa + ti → mīmāṃsati

Final m becomes n in front of v.

• जगम् + वत् → जगन्वत्

  jagam + vat → jaganvat

Final s

A final s changes in one of two ways:

• s changes to t
• s disappears

s changes to t

The s in vas and ghas becomes t when in front of the s of a verb suffix.

• वस् + स्य + ति → वत्स्यति

  vas + sya + ti → vatsyati

• जिघस् + स + ति → जिघत्सति

  jighas + sa + ti → jighatsati

s also becomes t in some parts of the reduplicated perfect.

s disappears

s disappears when in front of d or dh.

• शास् + धि → शाधि

  śās + dhi → śādhi

Special Rules

These rules will always apply, with only a few extremely rare exceptions. The exceptions can be counted on one hand.

n → ṇ

• ṛ, ṝ, r, or ṣ,
• if followed only by vowels, kavarga, pavarga, h, v, y, or the anusvāra,
• changes n to ṇ
• if the n is followed by either a a vowel or these letters: m, y, v, n.
• If there is another n after the first one, then they change together.

The idea is this. The four sounds in the first line will leave the tongue in the retroflex position. The tongue stays there for the vowels, kavarga, pavarga, and some other sounds, and it will stay there unless any other sound is spoken. If nothing causes the tongue to move, then the third line comes into play.

• अरुन → अरुण

  aruna → aruṇa

• अर्जुन → अर्जुन

  arjuna → arjuna

• रामायन → रामायण

  rāmāyana → rāmāyaṇa

• कुर्वन्ति → कुर्वन्ति

  kurvanti → kurvanti

• ब्रह्मन् → ब्रह्मन्

  brahman → brahman

• ब्राह्मन → ब्राह्मण

  brāhmana → brāhmaṇa

s → ṣ

• k, r, and any vowel except a/ā,
• in spite of intervening anusvāra or visarga,
• changes s to ṣ
• as long as the s is not final and not followed by r.

• हविसा → हविषा

  havisā → haviṣā

• तिस्थ → तिष्ठ

  tistha → tiṣṭha

Exceptions are hiṃs and puṃs.

Charts

Special Principles