Filipinos learned their English from American teachers who came on several ships at the start of the 20th century. The biggest contigent came on the USS Thomas and from then on, American teachers who came to teach were called "Thomasites". While the teachers came from all over the United States, many came from northern or Yankee states such as New York, Massachusetts and some came from California. The teachers had the hard task of establishing a public school system where there was almost none.
But some of the teachers were clearly from the South. The Confederacy's defeat was still within living memory then and this probably led one teacher to write that the many of the teachers were ""a regiment of carpetbaggers, come to exploit the country in their small way." It was likely that the father of this teacher or she herself as a child saw what the Union troops did to the South and its aftermath. And probably she was well aware of the "Philippine Insurrection" that laid waste to some Philippine provinces.
Surely the English that Filipinos learned from the American teachers is not Southern but there must be one Southern characteristic that had an indelible impact on Filipinos. Not a few people in the South address their teachers as Ma'am or Sir. In the Philippines students still address their teachers that way. A historian correctly attributes this to the first American teachers. But here in the South, people still address you in that way as a matter of courtesy, even if buying at a McDonald's or at a supermarket.
The South in many ways is similar to the Philippines. Perhaps it is a legacy of similar histories.