aspell-br software package provides Breton dictionary for GNU Aspell, you can install in your Ubuntu 16.10 (Yakkety Yak) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install aspell-br
aspell-br is installed in your system.
Make ensure the aspell-br package were installed using the commands given below,
$ sudo dpkg-query -l | grep aspell-br *
You will get with aspell-br package name, version, architecture and description in a table
| Distro | Ubuntu 16 10 yakkety yak |
| Section | Text Processing |
| Package | aspell-br |
| Version | 0.50-2-6 |
| Description | Breton dictionary for GNU Aspell |
| Sub Section | text |