So… Turns out there is no shortcut to turn text to semibold in Apple Pages, from the iWork suite. There are shortcuts for bold and italic respectively, but not semibold (or light / ultralight for that matter) even for the fonts that support it.
The closest thing to a solution that I found is through Character Style:
– Select a piece of text, make it semibold
– In the Styles Drawer, under Character Styles, click on the little arrow next to “none” and “Create New Character Style From Selection”
– Assign a Hot Key to the newly created Character Style, by clicking the arrow next to it and Hot Key.
There are a few drawbacks to this approach, mainly that the character style you’re defining will be tied to a particular font, and that the only shortcuts allowed by the Hot Key setting are F1 to F6. If anyone has a better way, I’m all ears!