Why do commentators pronounce UMAGA as UMANGA?

Question

Tana Umaga is NZ rugby player

Answer 1

In the Pacific that's how we pronounce names due to the many dilects we have. Although we may have one common language, every village has their own dilect. Take for example in Fiji you pronounce the "TH" as "CA".

Answer 2

Tana Umaga is originally from Samoa and in Samoan, that's how the pronounciation works.  It's the same in Fiji, e.g. the main airport is in Nadi, which is pronounced Nandi.