Il n'y a pas de traduction. Le "t" est seulement là pour l'euphonie. (for the sake of pronunciation) Cependant, ce "-t-" s'insert seulement entre deux voyelles, sauf exceptions. Par exemple "Est-t-il" n'existe pas. XD

it's not a grammar particle and it doesn't have a meaning.The "t" is there because of the clash of vowel sounds between "a" and "i". You couldn't say "Comment va il?". Every time you make a question by putting the verb in front of the subject and your verb ends in a vowel, you have to stick a "t" to avoid a clash. This goes for "il", "elle" and "on".