Got to admit I am pretty firmly in "it is the box that holds apples" camp so none of my array, table, dictionary names are plural. Some time I comfort myself by saying "well, apple[5] just sounds better" but that is really up for debate.
I agree that when you use aliases for multiple tables when you use (Oracle, non-standard SQL joins) that it looks prettier, but you can also do that with plural table names.
Select employee.name manager.name from employee, manager where employee.manager_id = manager.id
But it doesn’t matter that much when you use the traditional join syntax:
Select employees.name, managers.name from employees left outer join managers as manager on employees.manager_id = managers.id
Still I prefer singular table names, just disagree that it was data people who preferred singular and why.
Of course, with aliases you can return the exact name you want with aliases:
Select e.name as employee, m.name as manager from employees e, managers m where e.manager_id = m.id
The "database people" OTOH tend to use singular, which goes at least as far back as C.J. Date. I'm not sure why, but perhaps it's because fully qualified field names read more natural.