Boilingbroke, we won't ask you for details, though I'm sure you have many!  You bring up the fun and adventure of traveling in unknown places, with language and custom challenges.  Translation tools do ruin some of that spirit! However, I can see the value of them as they are improved over time.  Imagine if people in countries at war could hear their own voices in their enemies tongues.  I'd like to think that would add an element of human connection or new dimension that isn't available now.

I am okay with using these translation tools when I know a little bit of the language, and can be reasonably confident I'm avoiding silly mistakes.  I often use Babelfish, and make my own changes or corrections to the translation -- it's a short cut.

I'd be nervous about using a tool completely blind.

Especially when things are being translater FROM English. Some phrases just make no sense in other languages.

Ok then Michael, yes yes it always comes down to you.

Excuse the diversion before the days of the Internet I would find myself in Delhi, Bombay, Kuala Lumpur etc all in the wee hours and all without reservations, and somehow I always got by using my own resources and those of strangers.

As long as you have a money and passport you will always get by. 

If not you, who?

If I am on a business tour of Tokyo, Shanghai and Seoul I do not consider that I should be responsible for 3 languages and 3 city street layouts.  English speaking and gridded New York City is an entirely different matter.

@DrT: I agree. Translation greatly takes away the richness from the words and leaves behind mere phrases logically connected to each other. This is why I haven't so far been able to enjoy any translated book. Yes you can grasp the content but the experience is not the same as reading the writer's original words.

Michael --

I don't know whether smartphones are necessarily less reliable than other methods.

For example, my memory fails me regularly, even in English, much less in foreign languages. Those little conversation books sometimes have mistakes in them, and don't cover all possible circumstances. Standalone translation devices are available, but then you've got more stuff to carry around with you.

The same goes for the GPS functionality. Again, I can't count on my memory -- plus, I get absent-minded when driving and regularly miss the turns I was supposed to take. I used to carry paper maps with me everywhere, as well as spiral-bound street atlases. The last time I got a new car, I threw away the full stack of them because I never used them anymore. They were cumbersome, hard to search, as prone to mistakes as anything else out there, quickly outdated -- plus, it's hard to drive and use a map at the same time.

When going someplace brand new for the first time for an important event that i want to be absolutely sure to get to, I do double-check my smartphone's directions online. But I've been doing that less and less lately because I've been finding fewer problems. A couple of years ago, my phone told me to go down a street that had been closed. And a couple of months back, it didn't know that a new high school had been built and tried to navigate me to the old one. It wasn't a big issue in either instance and didn't cost me much driving time.

Of course, a lot depends on the device you have, as well.

In the five or so years I've been using it and its precessor, my phone has never gone out on me -- it never broke, it never ran out of power (I have a charger in my car). Okay, I forgot to pay the bill one month and lost service, but that was all my fault, and I immediately made the payment and was reconnected in minutes. 

But also, I've been lucky (knock on wood) and never dropped it into the toilet, never ran over it with my car, and never had it eaten by my dog.

My kids, however, have had different experiences with their phones (different brand, different platform). They crash. They go slow for inexplicable reasons. Certain apps just stop working. If I was using one of those phones I would definitely have a backup system in place for all my critical phone-based activities such as navigation, translation, and Sudoku.

@Michael: Apart from the battery life, a big problem that I have seen is that these apps don't seem to work when you don't have an active data connection or when you're at a place where the wi-fi may not be working. That's because the dictionary resides on the web and apps don't store it locally. This greatly limits their usefulness. A good translator app should have a local copy of the dictionary database so it can work in offline mode.

Well, life can be hard. You are a visitor in the middle of New York City and all you have is your GPS. It dies. And you didn't feel the need to have a map or were listening to the turn by turn and not paying attention. I'm betting you would be lost then. Not me.