Two way language translators

Does she have an iPhone?
If so, buy iTranslate in the iPhone App Store. Done.

I use the free app Google Translate on my phone. Download the languages you want to use while traveling so you do NOT have to use data on your phone.
When we were traveling in Japan, I used it often in taxis and restaurants. Download English to Japanese and Japanese to English, uses Japanese characters for locals to read. .
Free, excellent and easy .

Thank you very much for the responses. My sister is interested in not having to depend on cell service. If you download Google translate does it work without cell service?

Yes, that is why you download it, no phone service needed. It is in your phone ready to be used. It was a life saver for us in Japan where we did not find much English spoken.Only download the languages you need. When I get home, I delete them from being downloaded. Then add new languages as I travel again. I used Arabic in Egypt just before COVID.
If your sister is on a tour she most likely won’t need to use a translator. We went several days ahead of a tour to Tokyo and stayed on after the tour for four days, used trains, and really needed this app.
We had a hospital ER visit too so it was Google Translate to the rescue! The doctor did not speak any English.

And Google translate also does well on translating printed signs, as well, tho my only experience is with Spanish

Google translate is also great for translating printed labels in grocery stores -- especially from lesser-known languages like Hungarian! Can't beat the price.

Once you download the google translate app, you then need to download the language you need from in the app. All free, but for it to work with no service you need both the app and the language(s) downloaded. Once you choose to download Japanese or any other language, then it works offline.

Test it by putting the phone in airplane mode and turning off wi-fi. If it works that way, it will work with no cell service anywhere you have the phone.

Thanks for all the information on Google translate. I did download it to see how it worked, and my sister is excited to experiment with it as well. I did download the Japanese translator, but when I disconnected my Wi-Fi I couldn’t use the microphone to speak into it. Does that sound right or am I doing something wrong? It seems like you can only use an off-line by typing in and getting the translation in writing as well. Please let me know if that’s not your experience.

I never spoke into it, just typed something like “I want to go to Cherry Blossom Hotel on XYZ Street” it then appeared in all Japanese characters which I showed to the taxi driver. Easy. Some languages do let you hear how it sounds.
Or I wrote “I fell and my right leg is in a lot of pain” showed
it to the ER doctor and his nurse who gave me a quick physical, and ordered xrays. And so on. He prescribed medicines and the hospital actually gave me instructions translated/ written in English.
If your sister stays with her tour guide, I doubt she will ever need to use this App. Perhaps she is arriving early and staying on longer after her tour as we did. Then this App is very good to have, actually a life saver at times.
We have traveled a lot of places all over the world and were surprised how little English was spoken in Japan, even at the front desk in our upscale Tokyo hotel. The Concierge did speak English and made dinner reservations for us.
We loved Japan! The beauty, the politeness of the people and I have never been in such a clean place. No litter at all. Passengers remove their trash including newspapers from the trains as they exit. Then they take it home! She has a great trip to look forward to.

Another shout-out for “iTranslate”

Anne,

A few thoughts on using automated translators. I've used Google Translate on several occasions in Europe including during a stay in hospital, and had somewhat mixed results. It worked to some extent but wasn't perfect.

I tried some informal "tests" on several occasions with native speakers of French, German and Italian and they indicated that the translator worked to some extent for simple statements but in some cases the translations weren't even close, and in others they were completely wrong. I've never tried it with Japanese, but that's a more complicated language than the "romance languages" so not sure how well it works.

I've also found that the concept of a "two-way translator" is somewhat cumbersome and doesn't always work well in reality. The locals quickly lose patience with that sort of thing.

It does seem that for the voice recognition part of Google Translate to work, you have to be connected to the internet. Fortunately, there are several ways to do that while traveling to Japan.

The easiest is to rent a portable Wi-Fi hotspot (also called a "jetpack" or "pocket wi-fi" or "my-fi"). These are small devices that pick up the 4G cell signal and convert it to Wi-Fi. You sign on to this portable hotspot just as you sign into any other Wi-Fi. This allows more than one person to connect at a time, and guarantees a strong and fast signal (since it's a Japanese model, it has the right frequencies).

There are multiple companies that rent these in Japan. You can reserve it before your trip, then pick it up and drop it off at the airport. Here's one summary I found; there are others:

https://nomadicboys.com/renting-pocket-wifi-in-japan/

You can also use public Wi-Fi (availability varies), or if your phone is unlocked and has the right frequencies, you can buy a Japanese SIM card.

I found that the camera function of Google Translate was much more useful than the speech recognition function. And I didn't find nearly much as much difficulty with the language barrier in Japan as I feared. If you want the full story of my trip of October 2019, including a section on language issues, here's my report. The language section is near the beginning, if you don't want to read the whole thing:

https://community.ricksteves.com/travel-forum/trip-reports/japan-2019-tokyo-hakone-national-park-kyoto-osaka-nagasaki