Is there a difference between a bit, a little bit and a little in the following context?
He is a little bit angry.
He is a little angry.
He is a bit angry.
Or do these sentences mean the same thing?
There is no difference in meaning between these three sentences, unless the speaker already establishes a context.
This means he is somewhat angry.
This means he is somewhat angry. No native speakers would infer any qualitative difference in how angry he is, unless someone first said
When used alone, "little", "bit", and "little bit" all mean "small". But if you emphasize "little bit" over "little" or "bit" then you are emphasizing how small it is.
If I walked up to you on Monday and said "I'm a bit hungry", and on Tuesday I walked up to you and said "I'm a little bit hungry", there is no way decide that I'm not as hungry Tuesday as I was Monday. But if on Wednesday I said "I'm a bit hungry", and you said "Have a hamburger", I could clarify that I'm not as hungry as you think, by saying "I'm only a little bit hungry".
They don't quite mean the same thing. It's subtle, though.
Using a "bit angry" would seem to indicate that he's something else, too, as "bit" indicates only one part of the whole.
Using a "little angry" is slightly more formal. Also contrast with the above.
In this case, the subject's mindset is all a little angry, as if it were slowly suffusing him.
By using two diminutive words together, it minimises the degree of anger. I imagine this being used either as a reassuring response to a question, or as sarcasm.
The three differ only in the degree of angriness. Here are the sentences in decreasing order of the same.
The first two are interchangeable in the order. But the third one has the lowest degree of angriness.