I want to understand the difference in meaning and the usage between the words "little" and "barely. I assume that barely is almost nothing, while little refers to a small amounts but bigger than barely. For example
Little is known in the literature about something ...
Barely is known in the literature about something ...
I think in the second sentence the meaning is almost nothing while in the first sentence it means few.
You are correct in your understanding of the difference.
Little is known of...
is more than
Barely anything is known of...
And in another example
The bikini covered her (a) little.
is more covered than
The bikini barely covered her.
"Little" can be a noun, an adjective, or an adverb. "Barely" is only an adverb. Some examples of the different ways to use "little":
It was only a little dog (adjective)
We see each other very little. (adverb)
If you want some ice cream, there's a little in the refrigerator. (noun)
While "little" can be used on its own to describe degree of something, "barely" is often paired with other adjectives or prepositions:
There was barely any food left after the family picnic.
Why did you wake me up? The sun is barely over the horizon.
Although like other adverbs it can be paired with verbs:
The candidate barely won the election in his home state.
So, in your example you would have to say:
"Barely anything is known about ..."
In terms of relative degree, as Peter's answer says, "little" is usually more than "barely". In order from greater to lesser degree:
There is a little ice cream left
There is only a little ice cream left
There is barely any ice cream left
In general, "barely" works better if you mean to exaggerate for dramatic effect:
I'm so tired I can barely stand up.
