(Greek > Latin: a suffix; one who believes in; one who is engaged in; someone who does something)

A student of or specialist in the German language, literature, and culture.
gerodontist, geriodontist
A dentist specializing in gerodontics.
One who specializes in gerontology.
glacialist, glacial geologist
1. Someone who studies geological phenomena involving the action of ice; especially, of glaciers.
2. Anyone who attributes the phenomena of the drift, in geology, to glaciers.
One who specializes in the scientific study of glaciers and their phenomena.
glossarist (s) (noun), glossarists (pl)
A compiler or writer of alphabetical lists of often difficult or specialized words with their definitions, often placed at the back of a book.
Someone who studies the origins of languages.
A collector of souvenir China.
1. Someone who has a theory advocating extension of the sphere and degree of government activity.
2. Anyone who has a tendency toward the extension of the role of government.
A strong adherence to the forms of words.
A specialist who studies writing systems.
One who is skilled in the craft of writing.
One who analyzes handwriting as an expression of character.
graphopathologist (s) (noun), graphopathologists (pl)
Someone who interprets personality disorders from the study of handwriting: Jack thought his uncle's job as a graphopathologist was super interesting because the penmanship of a person was the clue to any mental illnesses that a person might have.
A collector of religious tracts.