Experiments with language corpora

[DONJCH]

Can a confidence interval be calculated for any of these figures?

I am an expert of statistics, but I guess the answer can only be "yes" - we have a set of numbers, so they can be fed to any numerical method. The meaningfulness of the output is another matter.

Of course, it also depends on the measurement we want to evaluate. Qualitatively, from the graphs above, it seems that we can be relatively confident about Voynichese H1, while conditional entropy has strong variations depending on both the subset of the text (Currier A B) and the transcription system.

Did you mean to say you are NOT an expert in statistics rather than that you are?
The rest of your sentence suggests that you meant to say the former...

Not that it matters... but, if you are, please excuse the lecture!

Each of the points on your graphs will have an error bar around it, whether that is calculated or not.
This represents the (usually) 95% confidence limits for the measurement.
The error decreases with the size of the dataset.

So some of those conditional entropy values in your graph may not be (statistically) significantly different from each other and this information would be valuable to know. The 2.02 value for EVA may be essentially the same as that for the next language - or the uncertainty may be even wider, we just do not know.

A good software package would do all this for you.

This is not meant as criticism, your work is awesome!