If we’re talking explicit attribution, that’s a very loose convention that’s deviated from more often than not as the target audience gets older, and that attribution gets more and more implicit. Explicitly stating who’s speaking for the start of every dialogue has a bit of a “childish” feel to it, almost, and there tend to be options that read a lot more pleasantly. Children’s books will absolutely make it explicit who’s speaking all of the time, but I find adult-oriented works rarely do, in my experience.
You’ve been staring at the screen for what feels like a year now. The numbers have a pattern to them, you’re sure of it, but you’re stuck in the same loop - your brain begins to piece it together, getting closer and closer, noticing repeating sequences, until just at the last moment something doesn’t fit and it all comes apart. You’re sure that if you just keep at it a little more, think about it a little harder, you’ll get it eventually.
“Just what in the name of all that is holy do you think you’re doing? I asked you to run those tests an hour ago!”
This shrill voice you know all too well pulls you back to reality. You can only presume Bob is still soldering behind you regardless, undisturbed, as he always is. A look to the side shows what you expected - Mary, looking disappointed, arms crossed, with her icy cold stare pointed right at you. You’ve never liked that stare, it gives you the creeps.
“I’m working. I may not be working on what you want me to work on, but I’m working.” You sit up straight and turn your chair towards her. “Contrary to what you may believe, there’s more to this work than your tests.”
She inches a little closer to you, her disappointed look shifting ever so slightly into something else. Frustration? Anger? You can’t quite tell.
“Taylor, need I remind you I’m your boss? When I tell you to do tests, you do tests.”
You’re tempted to just give in, but not this time. “I’ll get to those tests, but I’m figuring out these numbers first. We need these numbers figured out, remember? All your tests amount to nothing without -”
“SHADDUP YOU TWO!”
A thunderous roar eliminates any intention you had of finishing your sentence.
“Ya both can bicker ‘bout numbers and tests somewhere else dangit, you’re making my hands shake and these components are darn tiny. And, might I remind you both, expensive. Run yer tests, run yer numbers, I don’t care, just stop. Frickin’. Runnin’. Yer. Mouths. Already.”
You feel a strange sense of relief as Mary’s gaze shifts from you to Bob. You don’t even know why you feel that unsettled by her, not that it matters. After a few seconds, she sighs.
“Fine. Run your damn numbers then. But if I don’t get test reports on my desk by tomorrow morning, we’re having a talk about your productivity.”
Not a bit of explicit attribution there, but you can (hopefully - I won’t claim to be the best writer) tell who says what. And sure, names are mentioned, things are implied, and you could call that attribution, but at that point we’re back to “comprehension of the context will tell you who’s speaking”.