Update Speech Engine so messages are understandable

The current speech engine doesn't know how to speak some abbreviations and tends to read out digits individually. For example a message says "past waypoint 56 dist 18m" but it announces, "past waypoint five six d-i-s-t one eight m" the engine should be taught that "dist" is pronounced distance, 18 is eighteen, and m is meters.
It's very hard to decipher what it is saying.

There is also a message i keep getting that has no meaning to me. "Executing NAV Command ID#16" it would be nice to have that in plain words. I think it's related to DO_SET_CAM_TRIGG_DIST, but not sure.

NAV should not be pronounced N-A-V.

Start by locating the speech engine and the handling for messages such as "past waypoint 56 dist 18m" and "Executing NAV Command ID#16". Check how abbreviations, numbers, NAV, and DO_SET_CAM_TRIGG_DIST are currently represented, then define understandable spoken output and verify it against these examples.

Written by the indexing model from the issue text.