P29 · แล้วจึง Sewn Into the Word-Ending

"'He did A, then B.' Step one: put A's verb into your P28 done-hat, then swap the hat-tip's -a for -tvā:
dṛś's done-hat is dṛṣṭa→dṛṣṭvā (having seen); kṛ's is kṛta→kṛtvā (having done); gam's is gata→gatvā (having gone).
The rule is just one line: the done weak stem + -tvā = 'having ...ed, then.' Only the very last verb in the sentence — the finite verb — changes for person and tense; everything before it, the string of 'thens,' never changes."

▸ The then-hat is an indeclinable (Thai term อพยยะ): it doesn't change for the subject's gender, number, or case — one hat fits every occasion. This is exactly why it can be sewn on one after another without limit.

"There's one exception, easy to spot at a glance: when the verb's head carries an accessory (a prefix, upasarga), the tail is no longer -tvā but -ya instead.
ā+dā→ādāya (having taken → 'taking along, together with'); pra+viś→praviśya (having entered); pari+tyaj→parityajya (having given up).
The whole decision comes down to one step: first check whether the verb's head has an accessory — none, use -tvā; has one, use -ya."

Six actions in one sentence (the แล้วจึง machine at full speed) — sewing the whole story into one breath:

vīraḥ sāgaram dṛṣṭvā, setum kṛtvā, pāram gatvā, nagaram praviśya, devīm ādāya, punaḥ agacchat.
"The hero — having seen the ocean, having built a bridge, having crossed to the far shore, having entered the city, having taken the queen along — then went back."
Six actions, five 'then-hats' (dṛṣṭvā/kṛtvā/gatvā = -tvā; praviśya/ādāya = -ya) + one finite verb, agacchat. Thai needs five แล้วจึง; Sanskrit sews them all into the word-endings.

This lesson's sound-change rule (C6, taught alongside the vocabulary): the most familiar accessory in prefixed -ya participles is pari-. When it enters everyday Thai it voices: pari→บริ (ป→บ). Its natural carrier word is บริจาค ← parityāga (the noun of √pari-tyaj 'to give up,' everyday meaning 'donation') — a direct relative of this lesson's -ya example, parityajya; the Decoder card C6's original example, parisuddhi→บริสุทธิ์, shows the same pari→บริ pattern. The voicing of an initial consonant cluster (ปร→บร, วย→พย, วร→พร) = C6.

ādāya's second identity: this class of -ya participles often fossilizes into a quasi-postposition — ādāya "bringing along/together with," adhikṛtya "regarding," ārabhya "starting from." Thai also has verbs that grammaticalize into prepositions (like เอา...มา), which can serve as a cross-linguistic analogy.