The French Canadian government knows exactly what is going on at the end, but they can't warn English speaking countries.
Even though English is the only language affected, it's only a matter of time before the disorder spreads to speakers of non-English languages. Many languages have borrowed English vocabulary, so it's plausible that the disease could jump to other languages using English loan words as intermediaries.
The disorder could eventually infect non-human species. For example, dogs understand basic verbal commands. Higher order primates and large parrots such as African greys can understand dozens of human words. Earth isn't just looking at a human holocaust, but a multi-species holocaust.
The translated French announcement says to avoid terms of endearment such as "honey" and "sweetie." What does Sydney reflexively say often when she finally gets through to her kids?
As the infected son lay dying, he mimics a child's cry and "mommy" with eerie perfection. It's clear that the infected parrot the last sounds they hear, and also attack the source of that sound. So...either he murdered that baby, or was near whoever did. Furthermore, it's fair to say that every infant and toddler in Pontypool is dead, since they generally don't keep quiet unless physically restrained.
It's a small town, so everybody probably knows everybody else in some capacity. The obits that Grant reads are probably hard enough for Syd and Laurel-Ann to hear, but then Grant gets to a few Drummonds. Laurel-Ann doesn't seem to react to the fact that (likely) some of her close relatives are among the confirmed dead. Although, this is just before she starts to succumb to the infection herself, so it's she's already losing her grasp on sanity.
This troper always found it a bit odd that they'd speak French as a way to get around the issue with understanding words being a cause of infection. Although it works in theory, it always struck me as more of a temporary measure. The more obvious choice to me would be to speak Welsh. Not only is it very different to English it's also very uncommon; The Welsh-speaking Communities in Canada are, as far as I can gather, both small and relatively centralized to Ontario (In fact, Pontypool was founded by Welsh settlers and named after Pontypool, their hometown). Finally a lot of Welsh words fall into the Kill= Kiss Category when compared to English ones. For example the Welsh word "Ci" (Pronounced "Key") means "Dog"; "Moron" means "Carrot"; It just strikes me as very strange that people in a region where they use such an unusual language would instead choose to use a relatively widespread one to avoid a virus spread by words.
Welsh would probably be a better language to speak to avoid infection, seeing as how it's not a romance language and is very far removed from English, but I think far fewer people know how to speak Welsh than how to speak French.
You could also eventually quell a fire by spitting on it, but a hose is the better option. Welsh isn't helping anyone.
Welsh would help people insofar as it's far less common. French is common worldwide and, as the previous troper mentioned, it's a romance language. The virus doesn't pass through language itself, but through understanding the language, and less people understand Welsh than French. Viruses evolve, it would evolve to a more commonly spoken language before it evolved into Welsh. Of course it's not practical compared to French, but it strikes this troper as a more permanent solution and yet nobody even mentions the possibility.