Traveling alone to Rio / only speak english?

I am traveling alone for two days/one night to Rio en route to Buenos Aires...but I only speak english. Is this going to be a major problem? Also, will I be safe traveling alone in this city?

This is a topic you'll find A LOT of opinions on. You might try the "forums" area of the www.tripadvisor.com website for further reading. This topic (Rio's safety & traveling as a first-timer) has been discussed quite a lot. The question itself implies that you're moderately aware of the challenges and risks of visiting Rio for the first time... especially if you're not familiar with Portuguese.

In general, many people have done this. The most important thing is to use common sense, stay away from the beaches at night, use taxis (vs. buses), find a good hotel in the South Zone (Ipanema or Copacabana), don't carry valuables with you, etc. (Be a minimalist when you're outside the hotel... and only carry what you really need for that particular outing).

Try Ipanema beach during the day... and a tour of the Christ statue (Corcovado) through your hotel if possible. The views from the Christ statue are amazing. Just do a search online... or with Webshots, Flickr, etc.

Take pre-paid taxis from the airport (easier for a first-timer) or arrange a hotel transfer. Metered taxis are cheaper... but maybe a bit more difficult for a first-timer. Pre-paid taxis are purchased from inside the GIG airport.

There are ATM machines on the upper floor at the airport. Near the food court. You'll normally get a better exchange rate with ATMs vs. money changers (in the airport or elsewhere).

Again, use common sense. Most crimes against tourists are muggings. And, they aren't THAT common. But, they do happen! The muggers are mostly after your stuff... and may use a knife or gun to encourage you to give it up.

Why are you coming to Rio? There is 50% chances that you will be robed or get shot so I sugest that you go Florian贸polis SC.

People will not understand you...in Brazil they speaks Portuguese.

Like take_me_ says, use common sense and be street smart. If you go looking for trouble it will find you. Head for Copacabana or Ipanema and enjoy the beach, sidewalk cafes, and sites. Most people in the tourist areas speak enough English that they will understand what you want. Be on the lookout for little kids, especially groups of them--they are the ones most likely to attempt to steal your possessions/money. Enjoy yourself, but be street smart.

Spent a week in Rio last year speaking little Portuguese, had probably the best time of my whole 8 months travelling. Lack of grasp on the language wasn't a problem, just make an effort and you'll be alright.
Don't miss out Rio whatever you do!
Stay in a good hostel (we stayed in botafogo - it was safe to walk around at night) and you'll meet loads of people to go out with so you wont be on your own.
Just be sensible and don't hang around the beaches after sunset and make sure you go to Lapa for a great night out.

In Brazil we speak portuguese, but everybody will be more than please to try to help you. Specially in Rio, almost everybody speaks english, I believe that you will have no problems at all. It is not so safe in Rio, so try to not go so far from the hotel and not leave alone at night. although is not so safe, is full of foreign people there, most of italians....
Enjoy your trip, and welcome!!!!
PS: When you there try our 'caipirinha' the best drink ever!!!