How do one know its a freehold you are buying and not a 30y lease?

Condos are registered at the land department i understand but are these docs in English or Thai or both?

The title documents are in Thai only.

The rear side of the title document will tell you who the owner of the land / condo is and if there are any encumbrance such as mortgage, lease, habitat, usufruct, superficies or servitude registered.