Cake\ORM\Behavior\TranslateBehavior::buildMarshalMap PHP Method

    public function buildMarshalMap($marshaller, $map, $options)
    {
        if (isset($options['translations']) && !$options['translations']) {
            return [];
        }
        return ['_translations' => function ($value, $entity) use($marshaller, $options) {
            $translations = $entity->get('_translations');
            foreach ($this->_config['fields'] as $field) {
                $options['validate'] = $this->_config['validator'];
                $errors = [];
                if (!is_array($value)) {
                    return;
                }
                foreach ($value as $language => $fields) {
                    if (!isset($translations[$language])) {
                        $translations[$language] = $this->_table->newEntity();
                    }
                    $marshaller->merge($translations[$language], $fields, $options);
                    if ((bool) $translations[$language]->errors()) {
                        $errors[$language] = $translations[$language]->errors();
                    }
                }
                // Set errors into the root entity, so validation errors
                // match the original form data position.
                $entity->errors($errors);
            }
            return $translations;
        }];
    }