[hylaride]

I'm Canadian and I switched from an ISP headquartered in Ontario to one headquarterd in Quebec (Teksavvy to Bell because of a bulk agreement my building got) and now half my youtube ads are in french, despite me living in Ontario.

Don't care either way, but it does make you think...

[shadowgovt]

That's a targeting limitation.

I don't know OTOH whether "target audience's spoken language" is one of the signals an advertiser can key into in targeting an ad (at a glance, it looks like it might be). But (a) advertisers don't always have that signal and (b) advertisers themselves aren't always savvy enough to set it (how many American advertisers targeting Iowa actually tag their ads as "in English?"), so you'll end up with region targeting as a proxy for language targeting.

In your case, it's probably that the ad engine doesn't have enough info on you so it's falling back to geotargeting and hoping for the best (are you running with JavaScript disabled? Clearing cookies frequently? Avoiding logins? If so, these are all things known to decrease ad signal quality).

[hylaride]

That's the point. Youtube/Google knows who I am and I'm logged in - my preferences are all set to english and my searches, videos watched, etc are all 99% english, with the rest being with english subtitles.. I'm not talking about banner ads on random websites.

They literally have first class data.

[shadowgovt]

Good point. Another hypothesis is that individual advertisers aren't using that data.

Back in the day, I had a front-row-seat to this process and I observed how often advertisers simply misconfigure a campaign and under-target it. If you don't set a targeting preference for a given indicator, the default can be to target everyone regardless of what that indicator says about them.

It might be the case that advertisers are saying they want to target you anyway (or failing to say one way or the other) even though they should have enough signal to know it's a wasted impression.

[hylaride]

Yeah, that makes sense as well. The french ads come to me in waves and I can see lazy advertisers just "targeting quebec" or "all french regions" for the french runs.