French -iss-

← Italian -isc- (cognate)

← Latin -sc- (mention)

← Latin -esco (mention)

← Portuguese -ec- (cognate)

← Portuguese -esc- (mention)

← Portuguese -esç- (mention)

← Romanian -esc- (cognate)

← Romanian -ăsc- (mention)

→ French -is (mention)

→ French abâtardissement (mention)