Alexa and Google Home are not your only choices when it comes to Voice Assistants. Mycroft is a promising project that hopes to provide all the same features but with more privacy. It's still just getting started, but it's off to a good start.
If you want to test it out you can build one yourself out of a raspberry pi.

The steps for building your Picroft can be found here:
https://mycroft.ai/documentation/picr...

Other links you'll use:
https://github.com/MycroftAI/mycroft-...
https://mycroft.ai
https://mycroft.ai/to/picroft-image

Parts -
Banggood links:
http://drzzs.com/confmic
http://drzzs.com/rpi3b+
http://drzzs.com/rpiPSswitched
http://drzzs.com/MiniSpeakers

AmazonUS:
https://amzn.to/2XaernZ Rpi3b+
https://amzn.to/2IjAHbC Pi Power Supply
https://amzn.to/2IkDYY5 Jabra 410
https://amzn.to/2GO7LX0 PS3 eye
https://amzn.to/2DUdIyf Mini Speakers

AmazonUK:
https://amzn.to/2TUYvUJ Rpi3b+
https://amzn.to/2S6eYUh Pi Power Supply
https://amzn.to/2S6fIZz Jabra 410
https://amzn.to/2TWxssa PS3 eye
https://amzn.to/2BGJzCh Mini Speakers

Yaml Examples (verify formatting, posting here usually screws it up)
Config.yaml
mycroft:
host: 192.168.1.55
notify:
- platform: mycroft
name: picroft
input_text:
picroft:
name: Picroft

Automations.yaml
- alias: picroft tts
id: picrofttexttospeachbox
trigger:
platform: state
entity_id: input_text.picroft
action:
service: notify.picroft
data_template:
message: '{{ states.input_text.picroft.state }}'