1. I want to change 2 Images , the word "Images" in the Splash page to my own language.

Unfortunately, this in not possible in the current version of Juicebox (v1.3.3) but this text will be added to the languageList options in the next version of Juicebox-Pro.

2. My template don't have auto play when Splash is enabled. Still more, the auto play button doesn't appear.

Unfortunately, this is a known bug (autoPlayOnLoad is not respected when a gallery is opened from the Splash Page).
However, this bug has already been addressed and will be fixed in the next version of Juicebox-Pro.
In the meantime, you could perhaps disable the Splash Page by setting showSplashPage="FALSE" (in JuiceboxBuilder-Pro's 'Customize -> Splash Page' options).
Otherwise, instead of using the Splash Page, you could use a standard HTML link in your web page to open your gallery's 'index.html' page.

3. I want to add 2 flags (Russia and Vietnam) to translate title and description of each picture.
Can you tell me how to do that, I can creat 2 Slide with 2 Language and link that with a flash on each site ?

Juicebox does not have built-in support for multi-language titles/caption. However, you could achieve your goal with one of the two suggestions below.

(1) Create two separate galleries, each using (and sharing) the same images but with different titles and captions, and then link each of your flag images to the appropriate gallery.

... or:

(2) You could give each image a title in Russian and a caption in Vietnamese. You could then choose not to display the title or caption in the gallery at all (using captionPosition="NONE").
You could then use links (from your flag images) to set a JavaScript 'language' variable and, depending on which language has been selected, you would extract and display either the title (Russian) or caption (Vietnamese) elsewhere (outside the gallery) on your page using the Juicebox-Pro API: http://www.juicebox.net/support/api/

Here is an example.
First create a sample gallery with JuiceboxBuilder-Pro and enter your Russian text in the image titles and the Vietnamese text in the image captions (on the 'Images' tab).
Next, replace the gallery's 'index.html' page with the following code:

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <meta name="apple-mobile-web-app-capable" content="yes" />
        <style type="text/css">
            body {
                margin: 0px;
            }
        </style>
        <script type="text/javascript" src="jbcore/juicebox.js"></script>
        <script type="text/javascript">
            var language = 'Russian';
            var jb = new juicebox({
                captionPosition: 'NONE',
                containerId: 'juicebox-container',
                galleryHeight: '400',
                galleryWidth: '600'
            });
            function displayText() {
                var image = jb.getImageIndex();
                var info = jb.getImageInfo(image);
                var text = '';
                if (language === 'Russian') {
                    var title = info.title;
                    text = title;
                }
                if (language === 'Vietnamese') {
                    var caption = info.caption;
                    text = caption;
                }
                $('#output').html(text);
            }
            jb.onImageChange = function(e) {
                displayText();
            }
            $(document).ready(function() {
                $('#russian').click(function() {
                    alert('Russian language has been selected');
                    language = 'Russian';
                    displayText();
                });
                $('#vietnamese').click(function() {
                    alert('Vietnamese language has been selected');
                    language = 'Vietnamese';
                    displayText();
                });
            });
        </script>
        <title>Test</title>
    </head>
    <body>
        <div id="input">
            <span>Language</span><input id="russian" type="button" value="Russian"><span id="display"></span><input id="vietnamese" type="button" value="Vietnamese">
        </div>
        <div id="juicebox-container"></div>
        <div id="output"></div>
    </body>
</html>

Open the page in a browser and click the links to display either the Russian text (titles) or the Vietnamese text (captions).

(4) This is another known bug (autoPlayOnLoad does not function in Chrome on Android devices and the Audio Button initially shows the wrong status).
It is unfortunate that you have run across a number of known bugs but please be assured that we aim to fix all known bugs and appreciate users taking the time to report problems to us.
This issue has also been addressed and the fix will be included in the next version of Juicebox.
Thank you for reporting the problem.

If you would like to be notified when a new version is released, please join our mailing list at the foot of our homepage: http://www.juicebox.net/#logo-splash
... follow us on Twitter @JuiceboxGallery
... or subscribe to our blog RSS feed: http://juicebox.net/blog/

(5) Unfortunately, we are unable to support Opera Mini for mobile devices. Opera Mini is not a fully-featured browser (it has many features removed from the full version and has limited JavaScript support) and, as such, Juicebox will not function correctly in Opera Mini.
Please see this web page detailing the limitations of Opera Mini's JavaScript support: http://dev.opera.com/articles/view/oper … javascript

(6) Set showInfoButton="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> Button Bar' section) and the Info Button will be displayed in the Button Bar.
This will override the default behavior of the overlay and all elements positioned on the overlay will be toggled on or off when the user clicks the Info Button.

This is my bugs when using Juicebox-Pro, hope team will develop new version soon !

[Post edited for formatting.]