Tagalog ay (24)

[potet]

Thank you Cena RESTY and Victoria ANDERSON for your answers.
They made me think a lot yesterday night, and I think I have come up with
the solution.

1) The sentence is correct and of the equative type (A = B).
English: A is B.    Tagalog: B ang A  > ang A ay B.

You can fill the A and B slots with practically any full word. You can also
fill them with clauses; each clause is case-tight; only the case of the slot
is determined by the pattern. Once you have filled the slots with clauses,
all you have to do is replace a repeated item by a pronoun etc.

2) Thus I analyse the sentence as follows:
(For the sake of clarity, I have replaced the abbreviation _ng_ by _nang_,
and _kang_ by _ka-ng_.)

B[Ginagawa ka-ng kasing baba nang nagkasala sa iyo] ang A[paghihiganti].
> Ang A[paghihiganti] ay B[ginagawa ka-ng kasing baba nang nagkasala sa
iyo].
"Revenge makes you as low as the one who did harm to you."

in which
(cases: FF = focus; NFD = non-focus direct; NFI = non-focus indirect)

B[ginagawa ka-ng kasing baba nang nagkasala sa iyo].
B[be-doing / you-sg.-FF-linker / as / low / NFD marker / has-harmed / PREP /
you-NFI]

In other words, _paghihiganti_ "taking revenge" is the focus item at the
level of the sentence, while _ka_ (in _ka-ng_) is the focus item within the
clause that fills slot B.

3) Obviously, the underlying clause filling slot B was

[ginagawa ka nang paghihiganti na kasing baba nang nagkasala sa iyo]
[be-doing / you-sg.-FF / NFD marker / taking-revenge / linker / as / low /
NFD marker / has-harmed / PREP / you-NFI]

Then _paghihiganti_ was erased, and pied-piped its non-focus marker _nang_ .

4) This is now a sentence I made myself after this model. It should be
correct.

Ang pagpapakita nang pag-ibig nang mag-anak ay sinusulatan at tinatawagan
sila tuwing linggo.
FF A[showing / of  / love / of  / family] ay B[be-writing-to / and /
be-calling-(to) / them-FF / every-linker / week]

"To show love of one's family is (you) write and telephone them every week."
i.e. "To show your family you love them, you write and telephone them every
week."

Again, thanks a lot.

P.S. I won't expatiate on the term "focus" as used for Austronesian
languages. SCHACHTER's Tagalog grammar will give you a better explanation.

Jean-Paul G. POTET. B. P. 46. 92114 CLICHY CEDEX. FRANCE.