Please, thank you, sorry — the words that keep you polite.

• कृपयाkṛpayāplease (kindly)
• धन्यवादःdhanyavādaḥthank you
• अनुगृहीतोऽस्मिanugṛhīto'smiI am grateful / thank you (lit. 'I am favored')
• स्वागतम्svāgatamyou're welcome / welcome
• क्षम्यताम्kṣamyatāmsorry / please forgive (me)
• क्षन्तव्यम्kṣantavyamexcuse me / pardon
• आम्āmyes
• नnano / not
• अवश्यम्avaśyamof course / certainly
• साधुsādhugood / well done (expressing approval)