UKH

Who generally names new sport routes? The bolter or the first ascentionist? I've never done a first ascent of a sport route but every time I've done a trad FA, I've named the route so I just assumed the person to send a line named it. But then I started thinking about a lot of news articles I've read on UKC and for hard routes, it very much seems like the person who bolted it names it. Is this common at all grades? Do first ascentionists ever disagree with the name? If this is the case, whose name takes precedence?

Seems to be a continental (bolter) vs uk (FA) thing.

See Le Plafond de la Ligne Maginot (8c), Agincourt (8c) - named by Ben, correctly ignoring the opinions of locals who had bolted them but weren't good enough to climb them  

Generally it's whoever establishes the route, which is open to interpretation.

For trad routes it's almost always the FA, except in rare cases where it's been someone's longstanding project with a name that ends up being 'given' to someone else.

For most sport routes in mainland Europe it's the equipper whose names are respected, with the quite rare exception of notably hard routes, as above, where the FA has something to say

For UK sport it's quite rare that the equipper isn't the same person as the FA, so the issue is moot, but I'd say the FA opinion would probably win if the two disagreed.