What's the difference between spell an the vim-spell plugin?

Question

there are the spell function in vim and the vim-spell plugin, what's the difference?

Answer 1

'spell' is a builtin, the 'vimspell'-plugin is a 3rd party plugin which uses aspell or ispell to achieve it's goal.

according to :help spell:

 Note: There also is a vimspell plugin.  If you have it you can 
 do ":help vimspell" to find about it.  But you will probably want 
 to get rid of the plugin and use the 'spell' option instead, it works
 better.