Hey, taixzo!
I haven't manage to make the language model for Czech language yet, but in case you decide to make an option to use Google's voice recognition, here's a Czech translation for Saera.
By no means it is perfect, I'll take any suggestions.

I have one suggestion on my own - when you check for number of digits in a phone number, you should take into account that the length might be variable. For example, phone numbers in my country have usually 9 digits. But it can also be 14 or 13 digits, when you add the country code. And then there are special numbers with 3 (like 911) or 4 digits. If I were you, I would remove this condition.

Too bad I cannot test anything on the device, since my USB port broke off two weeks ago. It will take some time to get a new device.

EDIT: The translation is based on the deb posted in the first post as I believe it is the most recent one.