babelContextRouter.plugin.php

<?php
if($modx->context->get('key') != "mgr"){
    /* grab the current langauge from the cultureKey request var */
    switch ($_REQUEST['cultureKey']) {
        case 'en':
            /* switch the context */
            $modx->switchContext('en');
            break;
        default:
            /* Set the default context here */
            $modx->switchContext('web');
            break;
    }
    /* unset GET var to avoid
     * appending cultureKey=xy to URLs by other components */
    unset($_GET['cultureKey']);
}

de context settings

site_url       http://site.com/de/
base_url       /de/
cultureKey     de
--- also recommended to provide resource ids for the following settings
error_page     (id)
site_start     (id)

en context settings

site_url       http://site.com/en/
base_url       /en/
cultureKey     en
--- also recommended to provide resource ids for the following settings
error_page     (id)
site_start     (id)

nginx.conf

set $lang de;

# choose the language that appears first in the accept_language header
if ($http_accept_language ~* "(de|en)") {
  set $lang $1;
}

location ~ ^/$ {
  rewrite ^ $lang/ redirect;
}

location ~ ^/(de|en) {
  # redirect favicon.ico and assets/* requests to site root
  rewrite ^/(de|en)/(favicon.ico|assets.*)$ /$2 redirect;
  # main Babel rewrite
  rewrite ^/(de|en)/(.*)$ /?cultureKey=$1&q=$2 break;
  # MODX rewrite
  try_files $uri $uri/ @modx-rewrite;
}

location / {
  try_files $uri $uri/ @modx-rewrite;
}