Almost definitely yes. I've never known a tech company that truly deletes anything
Sometimes deleted stuff is archived offline or in slow warehouse databases that are not live, etc.
Basically, Facebook's always-on audio listening on their mobile app (Messenger I believe, but might be both these days) was giving this data. I can't remember the name of the company, but here is another tech company doing the same:
> Symphony uses just one: an app, downloaded to the cellphones of its more than 15,000 panelists. Audio recognition software then picks up whatever people are tuning into, wherever they’re tuning into it: their TV sets, their laptops, or their smartphones. “[It] measures everything you want to measure from one approach,” says Bill Harvey, a media research consultant who’s worked with Symphony
https://theringer.com/tv-ratings-streaming-nielsen-symphony-...
Depends, first of all storing compressed audio isn't that space-expensive, especially in some long term data storage like s3. Additionally they could only be storing the transcriptions, but not the voice behind them, which would be a lot less data.
We don't know as Amazon hasn't been very forthcoming about the privacy aspects of Alexa. I personally suspect they are keeping some voice information so they can use it to improve their NLP. I hope they are doing so in a way that is detached from accounts / IDs, but you never know.
Additionally, you can indeed delete a record of the query from the app, but who knows if the voice data or even the query itself is still stored after deletion, just not visible to us end users.