Possibility \#2

Possibility #2

When ṃ is followed by a consonant,

the ṃ may be transformed into the nasal of the vagga to which that consonant belongs.

e.g. kālaṃ + kata > kālaṅkata

In Kaccāyana this is called (31) vagg’antaṃ vā vagge.

Please take note of the nasal of each group

guttural	k	kh	g	gh	ṅ
palatal	c	ch	j	jh	ñ
cerebral	ṭ	ṭh	ḍ	ḍh	ṇ
dental	t	th	d	dh	n
labial	p	ph	b	bh	m

ṃ + guttural > ṅ

k	kh	g	gh	ṅ
kālaṃ	kata	kālaṅkata	pp. died, lit. time done
ahaṃ	kāra	ahaṅkāra	masc. “I making”
saṃ	khāra	saṅkhāra	masc. condition
atthaṃ	gata	atthaṅgata	pp. set, lit. gone home
saṃ	gha	saṅgha	masc. community

ṃ + palatal > ñ

c	ch	j	jh	ñ
dhammaṃ	ca	dhammañca	and dhamma
saṃ	chavi	sañchavī	adj. covered by skin
saṃ	jāti	sañjāti	f. birth, arising
saṃ	jhā	sañjhā5	f. evening
saṃ	ñā	saññā	f. perception

comm word

ṃ + retroflex > ṇ

ṭ	ṭh	ḍ	ḍh	ṇ
saṃ	√ḍaṃs > ḍās + *a	saṇḍāsa	masc. pincers
saṃ	ṭhāna	saṇṭhāna	nt. standing still
saṃ	ṭhahati	saṇṭhahati	pr. settles in

ṃ + dental > n

t	th	d	dh	n
saṃ	tāpeti	santāpeti	pr. burns
saṃ	thata	santhata	pp. spread
saṃ	dasseti	sandasseti	pr. explains
saṃ	dhāvita	sandhāvita	pp. transmigrated
saṃ	nicaya	sannicaya	m. accumulation

ṃ + labial > m

p	ph	b	bh	m
upa saṃ	padā	upasampadā	f. higher ordination
saṃ	phassa	samphassa	m. touch, contact
abhi saṃ	buddha	abhisambuddha	pp. woke up completely
paṭi saṃ	bhidā	paṭisambhidā	f. analytical insight
saṃ	majjati	sammajjati	pr. sweeps

Counter-examples:

taṃ kammaṃ > taṃ kammaṃ

saṃ khitta > saṃkhitta