public offsetExists (mixed $translateKey) Check whether a translation key exists

public setInterpolator (

public string offsetGet (string $translateKey) Returns the translation related to the given key

public string t (string $translateKey, [array $placeholders]) Returns the translation string of

public offsetUnset (string $offset) Unsets a translation from the dictionary

public string _ (string $translateKey, [array $placeholders]) Returns the translation string of

public offsetSet (string $offset, string $value) Sets a translation value

Source