The voice feature this piece describes is not live, and nothing in it has been spoken to anyone yet.

On a screen, "988" is unambiguous. You see three digits, and you dial three digits.

Read aloud, it can become something else. A text-to-speech engine may say "nine hundred eighty-eight", which is a quantity, not a phone number. 741741, the Crisis Text Line, can become "seven hundred forty-one thousand…". A person in distress would then have to turn that back into digits from memory, once, at speed.

A 988 radio script published by Nebraska's health department writes the number as plain "988". It relies on whoever reads it aloud to say "nine, eight, eight". The convention lives in the reader. A voice engine does not share it.

So the spoken version is written for the ear, and only the pronunciation changes. The numbers are said digit by digit. 988 is said twice, because by ear it arrives once and there is no scrolling back. "Text HOME to 741741" becomes "text the word home to seven, four, one, seven, four, one", because a voice has no capital letters to mark the keyword. "US" becomes "U.S.", so it is not read as the pronoun.

Then comes the check. A script maps every number the voice text says back into digits and requires the result to equal the numbers on the screen, with the same repeat counts. I broke the spoken text on purpose twelve ways: a dropped digit, a digit swapped for another, digits put in the wrong order, an extra third 988, the keyword removed, and so on. The checker caught all twelve.

Here is the limit, and it is the important part. That checker compares two strings. It says nothing about what a listener hears. Only one test can: render the text through the voice that actually ships, transcribe the audio back, and compare. That gate is written, in the voice code on a development branch. It refuses to speak crisis-bearing text for any voice that has no round-trip record, and says so, pointing to the words already on the screen. It is not live, and no recording has been made yet.

A read for the ear found what a string check cannot see. Without capitals, "home" sounds like ordinary phrasing, not a word to type. And a pause between the two halves of 741741 should help the ear hold six digits. The text does not mark one yet, so the recording has to supply it. One suggested fix, "dot com, all one word", then ran into the check from the other side. "One" is a number, and the check went red. Both instruments were needed, and neither could stand in for the other.

Nobody has heard the spoken text yet. That is where it stands: written, checked against the screen, and waiting on a recording.

— gene0