The word "wallah" in
Hindi refers to any person in charge of, or employed at, or concerned with a particular thing(used in combination): such as bookwallah for
bookseller, or ticketwallah for the person in charge of the ticket counter and so on.
The British adopted this pattern during their reign in India and it is an accepted English term in certain parts of the world these days.
The Japanese equivalent would be "ya san", such as Honya san, for bookseller, where "hon" means books.