Open the Tab Text to Speech and the window has no entries except the column names. Go to the Tab Flight Plan there you can select that a text will be spoken from the column TTS. If you have made a selection you can see this by looking at the tick marks. If there is a tick mark the text in the NavLog Waypoint Comment will be spoken.
Then you change back to the Tab Text to Speech, where you see an overview of all select trigger points with the associated text. Depending on the type of TTS, despite the Modify button you cannot change the text here of in the Flightplan, you have to make changes in LNM, those entries a connected with the Little Navmap, so if there is a change, it will reflect to the spoken text.
With a future version of BTI, it is planned, to have a choice if you want them having connected or not.
The Modify button opens the text-to-speech window. For Details see: Text-To-Speech-Window.
If you click on the Remove button the entry will be deleted, In the Tab Flightplan unticking the box has the same result.
If you click on the Show in Map button the location of the trigger is outlined. When flying and missing the trigger has no action, the text is not spoken.