The EASIEST and most RELIABLE device to get to talk is the IKEA Symfonisk $99 speaker. It is a pretty decent Sonos speaker under the IKEA labeling. This speaker works with Hubitat's built-in SONOS speaker integration and does a very good job at TTS.
The other two options you mentioned have some Pros and Cons to each.
The Google Home Mini can be used as a TTS device using Hubitat's BETA Chromecast Integration. While this works, it has some quarks. First, these devices often go unresponsive, requiring one to click the INITIALIZE button on the device details page within Hubitat. Second, this integration has been found to cause overall hub performance issues for some users. Since it's still classified as beta code, many, many months since its original release, I am personally not a fan.
Using an Amazon Echo device for TTS requires some custom community code. Choices here are @tonesto7's very full featured 'Echo Speaks' integration and my very simple 'Alexa TTS Manager' integration. Both integrations use the same behind-the-scenes technique to masquerade as a user logged into alexa.amazon.com within a web browser session. This is somewhat tricky since it requires a browser 'cookie' to be refreshed periodically to keep the user logged in. Take a look at both, if you're curious.
So, you have some options to consider. If you have any questions, feel free to ask.
This is an excellent idea as well! In order to do this, you create an Alexa Routine for each TTS phrase you want uttered. On Hubitat, you create a Virtual Contact Sensor that corresponds to each Alexa Routine. You then expose these Virtual Contact Sensors to Alexa via Hubitat's Amazon Echo Skill. This allows these 'sensors' to be used as the triggers for each Alexa Routine. Finally, use an App like Rule Machine to set the virtual contact sensors to 'open' (then 'closed' to reset the device for next time) to cause the Alexa Routine to be triggered and "Speak" your phrase.
So using the echo app i can only make 1 dot speak at a time and only once. I can go the route of an alarm but it does not speak and go off at what ever volume it was at before the alarm went off. I would like to have something tell them what they need to do, i.e. log into class, reading time, lunch time. Have the announcement repeat every few min until they acknowledge it with a push button or switch flip.
Do the children each have a SmartPhone? If so, you could accomplish much of what you're after by using Pushover Notifications. It won't be TTS, but you can use the [E] emergency prefix to send recurring notifications to their phones until they acknowledge them. You can even configure the phones to have these notifications break through silent modes on the phones to force an audible notification. This may be the easiest solution to what your trying to achieve.
Other options that come to mind, but I am sure you've already ruled out...
babysitter / nanny
call them throughout their day to ensure they are on schedule
This wasn’t the main part of your comment, but just letting you know that you can use Messaging/Announcement instead of Say, and there configure one of more Alexa devices.
In the spirit of @HAL9000's post, I want to also point out that using the Alexa app and RM, it is possible to make a Dot repeat an announcement until one or more specified switches/buttons are pushed.
Thanks i am going to try the smart phone route. As for the others. I am a flight medic so calling them is not a real option, no grandparents close, cant really be a flight medic from home. But there school is requiring them to log into online classes at certain times a day.
I had TTS working just fine to report alarm events that were triggered by Konnected zones over sonos speakers. A few weeks ago, the TTS just stopped working. I'm still getting the Hubitat notifications for the alarms but noting over sonos. Any ideas?
I would recommend giving anything that is accessed by your Hubitat hub over the LAN a fixed IP address. On my network this includes: both HE C-5 hubs, Lutron Caseta Smartbridge Pro, Sonos speakers, Harmony hub, and the computer I use for Node-Red.
I know this thread is a bit old, but I was looking for TTS today for alerting the house that there is a water leak. The only audio cable smart device I have in the house is an Ecobee smart thermostat that has Alexa integration. I was able to use @ogiewon's Alexa TTS manager to send it a message.
It works great.
Once I get homebridge setup and get an integration with Nest Protect, I am going to see if there is a way to get them to announce a message since there is one on every floor of the house.