Don’t talk aloud in the library.
Can I use ‘aloud’ or not, in the sentence above? From my Koran English dictionary, except ‘(idiomatic) cry [shout] aloud,’ they don’t use the word to denote ‘in a loud voice,' or it is archaic. And I can tell that it could be expanded into ‘laugh/groan aloud’ from Longman. Could it be further expanded into ‘talk aloud’?
Aloud does not mean the same thing as loud. Rather, aloud is the opposite of silently.
It's possible to read silently, and therefore, it is also possible to read aloud. Also, it's possible to think silently, and therefore, you can also say think aloud in contrast.
On the other hand, it's questionable whether you can talk silently, so talking aloud would also be dubious usage.
I think the sentence with an adverb loudly sounds natural, at least to my ears. That's because I have heard teachers and parents telling that to their children.
Don't speak/talk loudly in the library
On the other hand, I have heard natives advising their kids to read aloud as in here.
In addition, as you are concerned, an aloud is a word which means talking in high pitch/volume, not necessarily crying. WordWebOnline defines it.
