A teleprompter that follows your voice

Almost every teleprompter asks you to pick a speed before you start talking. You guess, you start reading, and within about thirty seconds you are either chasing the text or waiting for it. This explains what voice following actually does instead, the ways it fails, and how to tell in two minutes whether one works.

Why a speed slider cannot work

Nobody reads at a constant rate. You slow down on a name you want to get right, you speed up through a sentence you know well, and you stop entirely when someone asks a question. A fixed scroll has no way to know any of that happened, so the gap between where the text is and where you are grows the whole time you are speaking.

The usual fix is a foot pedal or a remote, which works, and which means you are now operating a machine while also trying to sound natural. The other fix is to keep the speed slightly too slow and let the text bunch up below the line you are reading. Both are workarounds for the prompter not knowing where you are.

What voice following actually does

It listens, works out which words you have reached, and moves the script to match. Pause and the text waits. Speed up and it keeps pace. Skip a paragraph and it works out where you have gone rather than carrying on from where it thought you were.

The difficult part is not recognising the words. It is deciding what to do when recognition is wrong, because it sometimes will be. A prompter that trusts every result will teleport you across the page on one misheard word, which is far worse than scrolling slightly too slowly. Good behaviour here looks boring: it refuses to jump further than you could plausibly have spoken, and it never yanks the page backwards when a guess is revised.

The four things worth testing

Read a couple of paragraphs aloud and stop dead in the middle of a sentence. The text should stop with you, not drift on. Then jump down to the last paragraph and start reading from there, and see whether it finds you or keeps waiting where you were.

Then watch the motion itself. Text that holds still and then lurches forward every second or so is technically following you and is genuinely unpleasant to read from, because your eye keeps getting pulled back to the movement instead of staying on the line. It should creep, not step.

Last, unplug the internet and do it again. Some voice prompters send your audio to a server to transcribe it, which means the feature stops on a bad hotel connection and your script has been somewhere you did not choose. On-device recognition keeps working and keeps the audio on your machine.

Where it still goes wrong

A noisy room, a second person talking, or heavy improvisation away from the written words will all make any of these lose the thread. What matters is what happens next: a prompter should tell you it has stopped following rather than quietly scrolling at a guessed speed and letting you discover it mid-sentence.

The other common cause is duller. Your Mac records from whichever input it thinks is the default, and if that is a headset sitting in its case on the other side of the room, nothing is being heard at all. It is worth knowing which microphone is actually selected before you conclude the feature is broken.

Promptur

Promptur is a Mac teleprompter built around this. Recognition runs on your Mac, so it works with no connection and the audio is never recorded, saved or sent anywhere. It is free, with no account and no subscription, and the strip can also be kept out of a screen share so the people on your call do not see the script.

It needs macOS 26 or later, because the on-device speech recognition it uses arrived in that release. There is more about it on the Promptur page, and a separate piece on keeping a prompter out of a Zoom screen share.