So, when I wrote my book, I will confess that I used adverbs in action description, but I made sure to use them sparingly. And I avoided using them in dialogue almost entirely. I know adverbs are not your friend in that regard, but is using them in dialogue EVER acceptable? I know this is mostly a matter of opinion and everyone will likely have something different to add, but I wanted to throw that question out there.
In my experience, adverbs are only useful on very rare occasions. When an action contradicts the characters words, for example. '"I love you too," she said spitefully.' In this instance, spitefully helps the sentence because it clarifies the speech in a way that extra speech would be cumbersome to accomplish. Sometimes adverbs can also save you a bunch of writing. One example I found is "The tears ran unchecked down her face." unchecked tells you that she isn't trying to stop them, but more importantly, saves a bunch of writing explaining that. Edit: Basically, kill any adverbs that aren't essential. If the adverb is already implied by the context ("Where am I?" he asked groggily, looking around blearily in confusion.) it's completely unnecessary as it's already implied ("Where am I?" he asked, looking around in confusion). As Stephen King said, Use adverbs sparingly, like they're $100 bills.
Unless you have a very specific goal in mind for your adverb, it's probably better to leave it out. Your dialogue should speak for itself. Instead of adding adverbs, consider changing the verb. He said/she said is perfectly fine, but sometimes using words like 'decided' or 'wondered' or whatever will work better in context.
of course it's acceptable sometimes... it just depends on the skill of the writer... the best ones can use them well on purpose... and lesser lights may get some 'right' accidentally! ;-)
Your actual question doesn't match the title. Adverbs as dialog attributes is always likely to be problematic at best and Tom Swifty at worst. But using adverbs in dialog is fine and shows something about the person if they use a lot.
Is the question regarding the use of adverbs inside dialogue, or in dialogue tags? If it's inside dialogue, go berserk. Like, really. People use adverbs when they talk. Dialogue without them can all too easily sound like an academic paper, or like your character has a stick up their arse.
This, definitely this. We use adverbs in our speech, it's a fact. More importantly, I support the idea that most people do NOT use proper grammar in their informal speech. Keep that in mind!
if your character is a person who'd use adverbs when speaking, then of course you'd use them in that character's dialog... just don't use them in the dialog tags, unless you have a very good reason and can do so effectively...