The Philippines call center isn't that surprising to me. It was a US colony for 48 years. During US colonialism in the Philippines a school system was established with English as the primary instruction language. By 1950 20% of the population spoke English. After WWII a large portion of their media was in English. The Philippines 1987 Constitution established Filipino and English as co-official languages.

I live in an area with a lot of Philippine immigrants. Even kids that just immigrated here speak English as well as the locals.

https://en.wikipedia.org/wiki/Philippine_English