aspell-et software package provides Estonian dictionary for Aspell, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install aspell-et
aspell-et is installed in your system.
Make ensure the aspell-et package were installed using the commands given below,
$ sudo dpkg-query -l | grep aspell-et *
You will get with aspell-et package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Text Processing |
| Package | aspell-et |
| Version | 1:20030606-27 |
| Description | Estonian dictionary for Aspell |
| Sub Section | Text |