How do you say I love Latin in Latin?

The Latin language is variously referred to in Latin: as Latinum, lingua Latina ("Latin tongue"), or just Latina (short for the preceding). To say "I love Latin" you would use the accusative (direct object) form of one of these plus the verb amo "I love":

• Amo Latinum

Amo [linguam] Latinam

You could also say Ego amare Latine