Canada is English speaking, apart from Quebec which has remained French speaking, with people of French origin. Ottawa and Gatineau are divided by Ottawa river, Ottawa being in Ontario on the English side and Gatineau being in Quebec on the French side. If you go into Gatineau all the signs are in French, but on the Ottawa side all the signs are both in English and then in French.
So this is a bilingual city really, and most of the people I got to know were from Quebec, living in Ottawa or Gatineau, their mother-tongue being French. But they were able to switch from one language to another in a jiffy, especially when I was with them. When I was out of the room the conversation was in French but as soon as I stepped into the room they changed into English. So I really need to brush up on my college French, I think both English and French are necessary when visiting this part of Canada.
And if visiting Quebec the people living there are less willing to speak English due to what happened between the English and French. So... French lessons!!
English and French are the official languages of Ottawa. There are approximately 125,000 Francophones and 600,000 Anglophones living in the area, but both languages are commonly used and have full equality and stutus. Whenever you see something written down (on a cereal box, road signs, whatever) it'll be written in both English and French.
Most services offered downtown or in the major shopping malls are offered in both languages. As you move out of the downtown area, French becomes much less common. The exception is the East end, which is still quite bilingual. All government services or customer service lines are bilingual.
You'll notice that most people who's first language is French can speak English, however most people who have English as thier first language speak very little French.
Since Ottawa is the capital of Canada, it's an officially bilingual city. Everything is available in English and French, and most people speak both languages. Although English is more common, either language can be used pretty much anywhere.
Because of the cultural diversity in Ottawa, there are two primary languages, French and English. Now from personal experience (this was a while ago, so things may be a little different) is that if you are seriously trying to speak the language of the people whom you are talking to, that they will appreciate your attempt at their language. However, speaking to them in their homes in an unknown language and getting upset if they do comply will probably offend them. So, attempting to speak their language will usually get you a friendly response and they will try and help you with whatever it is you are trying to do (example asking for directions).
Some people are surprised by the level of French that people hear in Ottawa. But believe me--it's perfectly normal. Quebec is literally just across the river, meaning that Anglo and Franco Canada are literally a river away from each other. Also, because Canada has two official languages and all federal government workers are required to be bilingual, English and French share an equal basis. So please don't be terribly shocked if you go into a tourist place and hear the person behind the counter say "Hello et bonjour."
However, English still prevails as the chief lingua franca of Ottawa, despite bilingualism.
However, it's handy to know a few French phrases if you go over and visit neighboring Quebec. The locals will always appreciate the effort, even if you only know a few words or sentences.
Ottawa is a bilingual city and you will hear both French and English spoken in the streets, stores and everywhere you go.
Please be tolerant of both english and french regardless of your own language, and people will do the same for you. And I have discovered that making a little effort in your second language can go a long way!