-ist
* Often denotes a specialist or expert in a particular field or activity: This includes professions like arborist (tree expert), soloist (singer performing alone), geographer (expert in geography), and calligrapher (expert in calligraphy).
* Can also indicate someone who adheres to a particular ideology or philosophy: This is seen in words like socialist, capitalist, and feminist.
* More specific and narrower in meaning: These words generally highlight the individual's specific area of knowledge, practice, or belief.
-er
* Often denotes someone who performs a particular action or activity: This includes words like writer, singer, painter, and teacher.
* More general and broader in meaning: These words simply indicate the individual's role or function.
So, why the difference?
It comes down to historical development and the nuances of meaning.
* -ist often comes from Greek or Latin roots and emphasizes a specific expertise or belief system.
* -er comes from Old English and Old French roots and generally indicates a more general action or role.
Here are a few additional points:
* Some words can end in both "-ist" and "-er" with slightly different meanings, like "artist" and "art-er."
* The ending "-or" is also frequently used to denote a person, especially for words of Latin origin like "actor" and "governor."
Ultimately, the choice of suffix is influenced by the specific meaning of the word and its historical development.