External Consonant Sandhi

Also known as: hal-sandhi

Click to scroll down:

• Terms
• The Principle
• Simplifying Words
• Rules for Final Stops
• Rules for t
• Rules for n
• Rules for m
• Rules for ḥ
• Changes in the Second Letter

This page covers the rules of external consonant sandhi. These rules describe changes between two words when the first letter is a consonant.

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

The Principle

Consonants will change to make things easier to say.

Given this rule, I strongly encourage you to speak these changes out loud.

Simplifying Words

All nouns that end in consonants must go through a two-part simplification:

Removing extra consonants

A word cannot end in a consonant cluster, with one exception. First, some examples of the general rule:

• भगवन्त् → भगवन्

  bhagavant → bhagavan

• अगच्छन्त् → अगच्छन्

  agacchant → agacchan

Now, the exception. If r appears in front of a stop consonant, and if the stop is not part of some suffix, then the stop remains.

• ऊर्ज् → ऊर्ज्

  ūrj → ūrj

• अबिभर्त् → अबिभर्

  abibhar-t → abibhar

Reducing to Eight Consonants

In external sandhi, all words that end in consonants must have their consonants reduced to one of these eight.

देवनागरी

IAST

क्

k

ट्

ṭ

त्

t

प्

p

ङ्

ṅ

न्

n

म्

m

ः

ḥ

To reduce a consonant, follow the steps below from top to bottom:

Stops become unvoiced and unaspirated.

• युध् → युत्

  yudh → yut

• भगवन् → भगवन्

  bhagavan → bhagavan

c, ś, and h are converted to k. If the c was a j before this reduction started, it might become ṭ instead.

• ऊर्ज् → ऊर्च् → ऊर्क्

  ūrj → ūrc → ūrk

• राज् → राच् → राट्

  rāj → rāc → rāṭ

ñ becomes ṅ.

ṣ becomes ṭ.

s and r are replaced by the visarga.

• गच्छामस् → गच्छामः

  gacchāmas → gacchāmaḥ

• अबिभर्त् → अबिभर् → अबिभः

  abibhart → abibhar → abibhaḥ

The letters that have not been considered here (ṇ, y, l, v) will never appear at the end of a word.

Special rules for words ending in aspirated letters

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

• The word starts with g, d, or b.
• The word ends with any voiced and aspirated sound, including h.

• दुह् → धुक्

  duh → dhuk

• बुध् → भुत्

  budh → bhut

This rule also exists in internal sandhi, with a few extra rules.

Rules for final stops

All final stops will take the voice of the letter that follows them. Vowels are voiced sounds.

• वनात् गच्छामि → वनाद्गच्छामि

  vanāt gacchāmi → vanād gacchāmi

  I go from the forest.

• वनात् पिता गच्छति → वनात्पिता गच्छति

  vanāt pitā gacchati → vanāt pitā gacchati

  The father goes from the forest.

• वनात् अगच्छम् → वनादगच्छम्

  vanāt agaccham → vanād agaccham

  We came from the forest.

The four final stops (k t ṭ p) become the nasal sound from their varga when followed by n or m.

• सुखात् नदति → सुखान्नदति

  sukhāt nadati → sukhān nadati

  He roars from happiness.

• जगत्-नाथ → जगन्नाथ

  jagat-nātha → jagannātha

  lord of the world

Extra rules for t

t becomes c in front of all hard palate consonants (c, ch, j, ch, ñ, ś) and becomes ṭ in front of ṭ, ṭh, ḍ, or ḍh (not ṣ). This result, by our general rule, takes the voice of the letter that follows it.

• वनात् चरामि → वनाच्चरामि

  vanāt carāmi → vanāc carāmi

  I walk from the forest.

• तत् छिनत्ति → तच्छिनत्ति

  tat chinatti → tac chinatti

  He cuts it.

• तत् जानामि → तज्जानामि

  tat jānāmi → taj jānāmi

  I know that.

Rules for n

Second Letter

Combination

c, ch

ṃś —

ṭ, ṭh

ṃṣ —

t, th

ṃs —

j, jh, ś

ñ —

ḍ, ḍh

ṇ —

l

m̐l (ṃl) —

other letter

n —

Rules for m

When -m is in front of a consonant, it becomes the anusvāra. Otherwise, it stays m.

• नरम् पृच्छामि → नरं पृच्छामि

  naram pṛcchāmi → naraṃ pṛcchāmi

  I ask the man.

• नरम् गच्छन्ति → नरं गच्छन्ति

  naram gacchanti → naraṃ gacchanti

  They go to the man.

• नरम् यच्छति → नरं यच्छति

  naram yacchati → naraṃ yacchati

  He restrains the man.

• नरम् अश्वः पश्यति → नरम् अश्वः पश्यति

  naram aśvaḥ paśyati → naram aśvaḥ paśyati

  The horse sees the man.

• पश्यामि नरम् → पश्यामि नरम्

  paśyāmi naram → paśyāmi naram

  I see the man.

Rules for ḥ

Click here to read about visarga sandhi.

Changes in the Second Letter

The changes below are applied after the first letter has already changed. Remember, the term second letter refers here to the first letter of the second word:

• सुखात् हसति

  sukhāt hasati

Doubling

ch can become cch after any vowel. It always becomes cch when either of these things is true:

• the letter follows a short vowel
• the letter follows the words mā or ā

• स्निग्ध-छाया-तरुषु → स्निग्धच्छायातरुषु

  snigdha-chāyā-taruṣu → snigdha-cchāyā-taruṣu

  Among (those whose) trees give thick shade

n and ṅ are doubled when both of these things are true:

• the letter follows a short vowel
• the letter is followed by any vowel (pure or compound)

• विषीदन् इदम् अब्रवीत् → विषीदन्न् इदम् अब्रवीत्

  viṣīdann idam abravīt → viṣīdann idam abravīt

  Despairing, he said this.

The letter h-

In front of h-, the four final stops (k t ṭ p) become voiced. The h- becomes the voiced and aspirated version of the final stop.

• सुखात् हसति → सुखाद्धसति

  sukhāt hasati → sukhād dhasati

  He smiles from happiness.

• वाच् हि → वाक् हि → वाग् घि

  vāc hi → vāk hi → vāg ghi

  speech, after all

The letter ś-

ś- becomes ch when both of these things are true:

• the first letter is ñ or c
• ś- is not followed by an unvoiced consonant

• तत् श्रुत्वा → तच् श्रुत्वा → तच् छ्रुत्वा

  tat śrutvā → tac śrutvā → tac chrutvā

  having heard that

ś- can become ch after k, ṭ or p, but the change is rarely made.