Tena samayena buddho bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme.At one time the Buddha was staying at Sāvatthī in the Jeta Grove, Anāthapiṇḍika’s Monastery. Tena kho pana samayena chabbaggiyā bhikkhū mahāhasitaṁ hasantā antaraghare gacchanti …pe….At that time the monks from the group of six were laughing loudly while walking in inhabited areas. …

“Na ujjagghikāya antaraghare gamissāmīti sikkhā karaṇīyā”ti.
ujjagghikāya → ujjhaggikāya (pts) | gamissāmīti → gamissāmīti nisīdissāmīti (pts)“‘I will not laugh loudly while walking in inhabited areas,’ this is how you should train.”

Na ujjagghikāya antaraghare gantabbaṁ.
ujjagghikāya → ujjhaggikāya (pts)One should not laugh loudly while walking in an inhabited area. Yo anādariyaṁ paṭicca mahāhasitaṁ hasanto antaraghare gacchati, āpatti dukkaṭassa.If a monk, out of disrespect, laughs loudly while walking in an inhabited area, he commits an offense of wrong conduct.

Anāpatti—There is no offense: asañcicca,if it is unintentional; assatiyā,if he is not mindful; ajānantassa,if he does not know; gilānassa,if he is sick; hasanīyasmiṁ vatthusmiṁ mihitamattaṁ karoti,if he merely smiles when something is funny; āpadāsu,if there is an emergency; ummattakassa,if he is insane; ādikammikassāti.if he is the first offender.

Paṭhamasikkhāpadaṁ niṭṭhitaṁ.The first training rule is finished.