Translation:Canadians speak English and French.
This assumption that Canadians speak English and French (français québécois) is a neocolonialist myth that doesn't include the vast First Nations communities that speak Cree, Inuktitut, Ojibway and other indigenous languages. Nor does it include many recent immigrants who are not capable of communicating in either of the 2 "official" languages.
Yes, often, because you are referring to, in this case, the "English language" or the "French language". That is, "English" and "French" are adjectives here. Essentially we're just dropping the noun from "la angla lingvo" or "la franca lingvo" so that we're left with "la angla" or "la franca".
Unless it is dead or constructed (It belongs to all the people of the world) and has no cultural ties to a specific place, then it must have "la," as in "la angla." Note that "anglan" is not capitalized -- it is an adjective to the omitted "lingvo," as in "la angla lingvo."
"Esperanto" and "Latino" stand alone because they belong to the world, so they are proper nouns and are capitalized.
So yeah... Hope I helped. This was all explained in the Grammar Notes of Languages.
Because "la franca" and "la angla" are short for "la angla lingvo" and "la franca lingvo". As someone helpful said earlier on this page, this happens with all languages that belong to a country our group of countries, but not to Latin, or constructed languages such as Esperanto and Volapuk. (You wouldn't normally say, "Mi parolas la Esperantan", for example. It's "Mi parolas Esperanton".