Question: I created a 12\*12 plane in three.js, and I tried to edit it's verticles between 2 rendering, but it doesn't work.

I added this code, but nothing changed:

```
ground.geometry.dynamic = true;
ground.geometry.__dirtyVertices = true;
ground.geometry.computeCentroids();

```

Code here: <http://jsfiddle.net/vpBEG/2/>

Thanks in advance,

Answer: 
YMS is kind of correct with his answer.

> 
> 1.What does screen reader support by PDF?
> 
> 
> 

The screen reader that has the most support is JAWS, this is because Freedom Scientific and Adobe have worked extremely close together. NVDA has pretty good support as well. ZoomText has hit or miss support in Adobe Reader, and next to none in Acrobat.

> 
> I mean, What should I use, If I wanted to create a PDF Reader(for example with C#)?
> 
> 
> 

Honestly, don't even try. It took Freedom Scientific roughly 10 years to get JAWS and Acrobat/Reader working together decently. 

> 
> 2.How can I use a special language(Such as Hebrew or Persian) in screen readers? Can I change default language to special language in a screen reader?
> 
> 
> 

See my [answer on localising strings](https://stackoverflow.com/questions/11260611/what-is-a-correct-approach-to-using-strong-em-tags-when-localising-strings/11265602#11265602), but JAWS does not even support those languages. So I would tag the first page as an image and put an alt of "This PDF is in Hebrew, please return to the main page to get a \_\_\_ version." I don't know those languages, so I don't know if it is more practical to provide a straight English version or a romanization of the languages you mentioned.
AFAIK, screen readers and PDF files (in general) do not get along very well. You can however use PDF files specially created to be used with screen readers. See this post for more details: [What are “PDF tags” and why should I care?](http://acrobatusers.com/tutorials/what-are-pdf-tags-and-why-should-i-care)

For a non-optimal solution, you will need a component that allows unicode text extraction from a PDF file. You will find many questions and answers about [PDF text extraction](https://stackoverflow.com/search?q=PDF+text+extraction) here in SO.