Internal Sandhi describes the phonological change within a word after a grammar ending has been added.

Sanskrit Sandhi

S Rule

When a vowel other than "a", a "k" or "r" precedes "s", s changes into ṣ.


  • karo + si ⇒ karoṣi
  • gaccha + si ⇒ gacchasi (remains in front because of "a")
  • deve + su ⇒ deveṣu
  • bhavat + su ⇒ bhavatsu (remains in front because of "t")

N Rule

When ṣa, ra, ṛ, or ṝ precedes n, n turns into ṇ which gutturals, labials and "y" potentially in between.


  • rāma + ena ⇒ rāmeṇa
  • rat + ena ⇒ ratena (remains insertion because of dental "t")
  • kārya + ena ⇒ kāryeṇa
  • viṣaya + ānām ⇒ viṣayāṇām
  • bheṣaja + ānām ⇒ bheṣajānām (remains insertion because of palatal "j")