/Library/Spelling not found
It's not /Library/Spelling/ it's ~/Library/Spelling/ &amp; yes, it is hidden by default, as is the entire ~/Library.

~/ is the standard abbreviation for Macintosh HD/Users/your name/[your Home folder] the equivalent of Windows' environmental variables like %appdata% etc.

To see it temporarily hold down the Option key and select Library from the Go menu in Finder.

To make it permanently visible, Show View Options for your Home folder. Check the box to show the Library.