He is an expert in comparative linguistics.

Computational linguistics is the study of analyzing human language with computers.

She is majoring in clinical psychology.

He is an expert in psychiatry.

He is an expert in theoretical physics.

He is an expert in phytopathology, making a significant contribution to agriculture.

He is an expert in biophysics.

Molecular biology is a field of study that understands life phenomena at the molecular level.

He is an expert in ethology, and his research is highly regarded worldwide.

I am majoring in developmental biology at university.