src/RequestApplication.php
public function t($category, $message, $params = [], $language = null)
    {
        $language = isset($language) ? $language : $this->language;
        return Reaction::t($category, $message, $params, $language);
    }
public function t($category, $message, $params = [], $language = null)
    {
        $language = isset($language) ? $language : $this->language;
        return Reaction::t($category, $message, $params, $language);
    }
Translates a message to the specified language.

@param string $category Message category
@param string $message  Message for translation
@param array  $params   Parameters array
@param string $language Language translate to
@return string