What's Ubuntu's default terminal spell checker?

Ubuntu apparently comes with two spell-check programs by default:

$ apropos spell
aspell (1)           - interactive spell checker
aspell-autobuildhash (8) - Autobuilding aspell hash files for some dicts
aspell-import (1)    - import old personal dictionaries into GNU Aspell
enchant (1)          - a spellchecker
enchant-lsmod (1)    - Show information about available spell-checking module...

enchant is also an ispell-compatible spell-checker, and is listed in the ISO manifest, so it is installed by default.

And though it is not installed by default, Vim's full-fledged versions also support spell-checking, and do better in more complex files (for example, spell-checking only text in HTML).

The program I needed was aspell. It's very simple to run:

aspell check ~/Documents/file

It will automatically check the file for spelling errors based on the locale set. More information about it can be found in the man pages.

Hope this helps someone!