Edit in JSFiddle

webshim.setOptions('forms', {
    //show custom styleable validation bubble
    replaceValidationUI: true,
    customMessages: true
});

//start polyfilling
webshim.polyfill('forms');

//render messages
$(function () {
    var renderMessages = function () {
        $('.getErrorMessage', this).html($('input[type="email"]', this).getErrorMessage());
        $('.validationMessage', this).html($('input[type="email"]', this).prop('validationMessage'));
    };

    //render/update on input and on start
    $('.message-test').on('input', renderMessages).each(renderMessages);

    //+ update on lang change
    $(webshim.validityMessages).on('change', function () {
        $('.message-test').each(renderMessages);
    });
});
//end: render messages

//render activeLang-select
$(function () {
    var langs = webshim.validityMessages.availableLangs.concat(['de', 'en', 'en-AU', 'en-GB', 'en-US']).sort();

    langs.unshift('');
    $('select.active-lang').each(function () {
        var select = $(this);
        var options = langs.map(function (lang) {
            return '<option>' + lang + '</option>';
        });
        var onLangChange = function () {
            select.val(this.__activeName || webshim.activeLang());
        };

        select.html(options)
            .on('change', function () {
            var value = select.val();
            if (value) {
                webshim.activeLang(value);
            }
        });
        $(webshim.validityMessages)
            .on('change', onLangChange)
            .each(onLangChange);
    });
});

<form action="#">
    <div class="form-row message-test">
        <label for="email">email with data-errormessage</label>
        <input data-errormessage='{"valueMissing": "Please enter your email adress.", "typeMismatch": "Your email is not correct."}' required="" type="email" id="email" />
        <ul>
            <li>$.getErrorMessage: <span class="getErrorMessage"></span>

            </li>
            <li>validationMessage: <span class="validationMessage"></span>

            </li>
        </ul>
    </div>
    <div class="form-row message-test">
        <label for="email2">email without data-errormessage</label>
        <input required="" type="email" id="email" />
        <ul>
            <li>$.getErrorMessage: <span class="getErrorMessage"></span>

            </li>
            <li>validationMessage: <span class="validationMessage"></span>

            </li>
        </ul>
    </div>
    <div class="form-row">
        <input type="submit" />
    </div>
</form>
<label class="lang-select">change lang
    <select class="active-lang"></select>
</label>