The Austroasiatic languages, including Vietnamese and Khmer, are a language family that includes many languages.

The Austronesian language family is one of the most widely distributed language families in the world.

He is an expert in ornithology, studying types of birds all over the world.

He is an expert in speleology and is exploring caves around the world.

He is majoring in meteorology at university.

He is passionate about his research in futurology.

He is majoring in analysis at university.

Let's eat lunch in the school cafeteria.

He is known as an expert in gerontology.

He is an expert in acoustics.