I'd like to know how to install a Dutch dictionary in the mail program Evolution for Ubuntu. In Preferences I can see which dictionaries (all English) are installed but not how to add another dictionary.
The package you are looking is called
To install from a command line, press Ctrl-Alt-t), and enter the command:
To install from Synaptic, follow these instructions (adapted from here):
Then open a new message and verify that the spell check works correctly.