Redactor Language Plugin

language.js

(function ($R) {
    $R.add("plugin", "language", {
        translations: {
            en: {
                language: "Change Language",
            },
        },

        init: function (app) {
            this.app = app;
            this.opts = app.opts;
            this.lang = app.lang;
            this.block = app.block;
            this.toolbar = app.toolbar;
            this.options = this.opts.languages;
            this.currentLangAttr;
        },

        start: function () {
            var dropdown = {};

            for (var key in this.options) {
                var value = this.options[key];

                dropdown[key] = {
                    title: value,
                    api: "plugin.language.set",
                    args: key,
                };
            }

            var $button = this.toolbar.addButton("language", {
                title: this.lang.get("language"),
            });
            $button.setIcon('<i class="re-icon-specialcharacters"></i>');
            $button.setDropdown(dropdown);
        },

        set: function (lang) {
            if (!this.currentLangAttr) {
                this.addAttribute(lang);
                this.currentLangAttr = lang;
            } else if (this.currentLangAttr === lang) {
                this.removeAttribute();
                this.currentLangAttr = null;
            } else {
                this.removeAttribute();
                this.addAttribute(lang);
                this.currentLangAttr = lang;
            }
        },

        addAttribute: function (lang) {
            var args = {
                attr: {
                    lang: lang,
                },
            };

            this.block.set(args);
        },

        removeAttribute: function () {
            var args = {
                attr: {
                    lang: this.currentLangAttr,
                },
            };

            this.block.toggle(args);
        },
    });
})(Redactor);

Standard.json

{
    "buttons": [
        "html",
        "formatting",
        "bold",
        "italic",
        "unorderedlist",
        "orderedlist",
        "link",
        "image",
        "video"
    ],
    "plugins": [
        "fullscreen",
        "video",
        "language"
    ],
    "toolbarFixed": true,
    "languages": {
        "en-US": "English (US)",
        "en-GB": "English (GB)"
    }
}

The redactor docs make it seem like fontawesome support is built in, is that true? https://fontawesome.com/v4.7.0/icon/language could be a good fit for the icon.

The font awesome CSS is not included

We could potentially submit a PR to the Craft redactor plugin to include classes for some of their other icons.

If that were possible, I think the globe would be the most logical fit. If not, the Omega from your screenshot in Slack works fine enough.

How could I test this out? Maybe on Viget.com staging?

As you know, urgency on this is very low, so no need to respond right away.

How could I test this out?

Spinning up a craft site locally and adding the plugin is likely the easiest method for testing. Not really a whole lot to test though...