Sorry, I see I missed the pronounciation of t in my post.
In north Indian languages there is a contrast between dental (think French te) t and alveolar T (as in English take), and between unaspirated t/T and aspirated th/Th. (Thus, altogether there are t, T, th, and Th; all unvoiced, i.e. different from d, D, dh, and Dh). English (or any Western European language that I know) does not distinguish all these, and that is the root of the problem. Often English t is close to Sanskrit alveolar unaspirated T and th is close to Sanskrit dental aspirated th. Unfortunately jyoti needs the dental unaspirated (i.e. very little breath, but soft) t.
To add to this, the South Indian languages do not always maintain the aspirated/unaspirated distinctions of Sanskrit. So, they transcribe Sanskrit alveolar T/Th as t when writing in English, and t/th as th.