Sinhala phrases are useless in Jaffna right which Tamil phrases do I actually need

Sinhala phrases will not actively offend, but Tamil is the primary local language in the north and east, and using a few Tamil words wins genuine smiles. Useful Tamil for tourists: "Vanakkam" (hello, palms together is even better), "Nandri" (thank you), "Sari" (okay), "Illai" (no), "Eppadi irukkireenga?" (how are you?), "Enna velai?" (whats the price? for shopping), "Saappidu" (food), "Romba nalla irukku" (very good/delicious), and "Pesa mudiyuma?" (can I take a photo?). English is widely understood in Jaffna town, hotels, restaurants and the main tourist sites, less so in surrounding villages. A few Tamil words plus English will get you through 100 percent of tourist situations. Avoid using Sinhala unprompted in conservative Tamil contexts; locals understand the polite intent but it can feel tone-deaf to the regional history.