chromium-l10n software package provides web browser - language packs, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install chromium-l10n
chromium-l10n is installed in your system.
Make ensure the chromium-l10n package were installed using the commands given below,
$ sudo dpkg-query -l | grep chromium-l10n *
You will get with chromium-l10n package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Language packs |
| Package | chromium-l10n |
| Version | 53.0.2785.143-1 |
| Description | web browser - language packs |
| Sub Section | Localization |