The effort of describing Tamil by Fr. Henriques to other missionaries started *before 1549 A.D*, and his grammar of Tamil in Portuguese (that is, describing Tamil in Portuguese) surfaced in 1549 A.D.
This particular hand-written manuscript was obtained (way back in the sixties) for our research from Lisbon, Portugal.
The following page is the first folio entitled "Arte Da Lingua Malabar":
The following page introduces the Tamil alphabet (as the missionary perceived it in the 16th century) in its own orthography:
Notice the segment on the first line "... ba be bi bo bu... " in the following document. Many of us from an older generation can recall our recitation of the English vowels: "a ஏ, e ஈ, i ஐ, o ஓ, u யூ," right? :) The Portuguese seem to have had their own recitation method ("ba, be, bi, bo, bu"). There's much more to know from this manuscript!