@nounbase lengthening before strong

Bases in atu अतु lenghthen

before non-/sambuddhi strong /su by atvasantasy...

Bases in as अस् lenghthen

before non-/sambuddhi strong /su by atvasantasy...

before /zi by sAntamahat...

Bases in an अन् lenghthen

before all strong by sarvanAmasth...

Bases in R ऋ replace R ऋ with ar अर्

before strong by RtoGi ऋतोङि

but not before non-/sambuddhi /su, by Rduzanasp...