Hak-kâ-fa

Thank you for asking me about these.I will reply to you as following:

• Since Hakka is a language of Chinese, what I use is Chinese characters therefore, and thus, the script is written in left-to-right, the same as Mandarin.
• It is hard to say. What I can confirm is that some of them can be used for other dialects of Chinese while some others can't.
• If I write it in the Hak-kâ-fa Pinyin(Romanised script), that will be Hak-kâ-ngî. But we don't use this Romanised script(As I know,it is used in Tanwan only in some special occasion.),and for instead, we use Chinese characters. In Chinese characters, it will be 客家語,which I suggest to use.

Thank you very much for your help and for forgiving my ignorance.