Drupal 7: Return field value from multilanguage node fields.

gistfile1.php

/**
 * Return field value from multilanguage fields.
 *
 * The priority is following:
 *  1. provided language,
 *  2. node language,
 *  3. undefined language
 *
 * @param $node
 * @param $field
 * @param null $langcode
 * @return mixed
 */
function _mymodule_get_field_value($node, $field, $langcode = NULL, $key = 'value') {
  $value = NULL;
  if ($langcode && isset($node->{$field}[$langcode][0][$key])) {
    $value = $node->{$field}[$node->language][0][$key];
  }
  elseif (isset($node->language, $node->{$field}[$node->language][0][$key])) {
    $value = $node->{$field}[$node->language][0][$key];
  }
  elseif (isset($node->{$field}[LANGUAGE_NONE][0][$key])) {
    $value = $node->{$field}[LANGUAGE_NONE][0][$key];
  }
  return $value;
}