The only meaning of the acronym SONA that I am aware of with regards to the Philippines is “State of the Nation Address.” The State of the Nation Address is given every year by the president of the Philippines. The last SONA, the 4th given by President Benigno Aquino III, was given on July 22, 2013. The SONA is required by the constitution of the Philippines and must be given before Congress on the 4th Monday of July of each year.
As far as the etymology goes, the phrase “State of the Union Address” comes straight from English. English is one of the official languages of the Philippines. Therefore, many English terms are used in the Philippines. This is one of them.
Of course, the words “state,” “nation,” and “address” have etymologies. “State” comes from the Latin word “status.” “Nation” comes from the Latin word “nationem.” “Address” comes from the Old French word “adrecier,” which itself has its roots in Latin.
Thus, the phrase “State of the Nation Address” comes to the Philippines from the English language, which got the words from the Latin.