A complication comes to mind.

The idea that you would have to be “listening” on the right frequency. It stands to reasons that T would be projected in multiple variants (frequencies) or multiple different strings and it would be necessary to be tuned in to the right one to “hear” it.

This draws us in a circle back to picking up (T) from the people who you are closest to. As we have agreed, the signal is there all the time but with people close to you, you become attuned to their/the correct frequency. Same with the dog knowing when you are coming home. It gets attuned.