What's the best translation app that converts speech to text offline?

I had similar frustration. I never found another translation app that would have all the features offline. However, I've been purchasing eSIMs, lately. eSIMs are cheap and some of the apps I use, including google translate, use very little data.

You can use Google Translate just the way you want.

First, download the German and Italian files. You do this by choosing the language you want to translate to. When the page comes up showing all the languages, to the right of the language is a little download button. Click on it and the language file will be downloaded into the app. Once the check mark appears, the language is downloaded.

Once that is done, go back to the translation page. Click on the microphone and say what you want translated. It will show up onscreen first in English then translated. No need to type anything.

I've been trying to reduce my dependency on G**gle, as I don't want everything I do to be harvested by them for marketing purposes... (Ok, enough of that....) I'm using Yandex Translate now, it works as you describe, where you download the language files and it works offline. I tried a few similar programs, but I like the way Yandex works better.

Did you test DeepL app already? The translation quality to / from German is much better than with GT. Not sure about the offline capability you asked for.

DeepL does not have an offline mode as it relies on the cloud for processing translations, but as Frank pointed out above, Google Translate does have an offline mode, which is very handy when you can't access the internet.

And for most travelers, the difference between Google Translate and DeepL is not a real issue, imo. I use DeepL, because I agree that it's a good translation system, but for the most part, Google Translate works as necessary, which is what most travelers are looking for.

Google Translate has an offline mode but the text-to-speech function is not available when you are offline. Writing out what I want to translate takes too much time during a rapid-fire conversation with an impatient native.

In other words, you can't use the microphone on Google Translate to speak what you want to translate into the phone when you are offline.

I haven't gone through the article but this might help:

https://belikenative.com/top-7-offline-voice-to-text-apps-for-translation/

What type of phone do you use? I believe Apple Translate also offers offline capability with languages that have been downloaded. It believe the live translation feature is only available for iPhone 15 Pro and newer. I haven't had an opportunity to try it in real life situations yet, but hopefully I'll get a chance to do that in the near future.

This fairly recent video provides some examples of how well it works - https://www.youtube.com/watch?v=ZqiGz0UhXj4 . This review is also recent and offers some comparison of Apple and Google - https://www.youtube.com/watch?v=tdLnZ9GPdMo .
There are lots of videos on the subject but these will provide some idea on how well they work.

Even with with the translation apps, I still try to learn a few of the common polite words and phrases for each country that I visit, rather than having to rely on the phone for small, simple conversations.

I can't guarantee that we'll have internet everywhere we go...

In other words, you can't use the microphone on Google Translate to speak what you want to translate into the phone when you are offline.

Is the issue you will solely be relying on wifi OR that your hikes will be remote enough that your cell phone coverage will be weak or unavailable?

If it's the former, it's worth the $20-$30 for an eSIM or other cell coverage options. If it's the latter, that does add a wrinkle.

I know, with Google Maps, even downloaded maps don't have many useful extra functions when offline - ie walking routes are hit or miss. I've rarely thought about the voice dictation aspect of it, but Google Maps does allow me to dictate into the app (via the APPLE keyboard/microphone vs the app's microphone button), so that little nuance shows me your device does matter and also your settings.

Knowing your cell phone model and what service plan you'll use/not use might help the discussion.

Also, your itinerary looks super fun, so remember to let us know how it goes when you return.

I agree with Tom. I was just getting ready to post a suggestion that you get an e-SIM. You shouldn't have any problems with internet in Austria and Germany. It's been a while since I've been to Italy, so I'm not sure what it's like there, but just in case, buy an e-SIM. It will cost anywhere from $5 to $30+, depending on how much time you need it for and how much data you want. That way you should have internet every place you go. I usually use Airalo and have always been happy with that. https://www.airalo.com/