Umami was named/Identified in Japan in 1908. That's still a pretty recent discovery compared to sweet and salt and the human timescale of discovering and naming flavors. So it isn't surprising that it is still working its way into people's consciousness and vocabulary. It is also subtle compared to the big 4 tastes.

US African here. I din't know what Umami is. Looked it up just now... sounds like it would just be classified as a subtle variation to "salty" to me?

No umami is a rich meaty kind of taste (also found in seaweed, cheese, mushrooms, soy sauce, some vegetables, ...) which has nothing to do with sodium chloride.

Cf. https://en.wikipedia.org/wiki/Glutamate_flavoring https://en.wikipedia.org/wiki/Umami

Fat, MSG, oils, etc. all impart a savory-style flavor that is called umami that has nothing to do with salt.

*not African. Phone autocorrected American to African and I've missed the edit window.

In the US, we are taught that this is called "savory".

Savory isn't really the same thing. Savory is mostly a contrast to sweet. So a savory quick bread would be made with herbs rather than fruits. It does overlap some insofar as a bacon bread could also be called savory.

I see. Thanks for clarifying!