Voices and languages
Readalix speaks with six different kinds of voice. They differ in where the speech is made, what they cost you, and how exactly the word highlight lands.
Where voices live
Two places, for two different jobs.
- The toolbarThe Voice button lists the voices for the language you are on, grouped by source. This is where you switch voice for the read in front of you, even mid-sentence.
- Settings, Languages & voicesOne row per language, and a Voices button on each row that opens that language's full list. This is where you download voices, paste an API key, hide the ones you never use, and drag the rest into the order you want.
The six sources
Inside a language's voice list, the sources are tabs: Browser, Microsoft, Piper, Kokoro, Gemini and OpenAI. A tab with nothing to offer in that language is shown but disabled, so you can see it was considered.
| Source | What it needs | Where speech is made | Counts against the daily allowance |
|---|---|---|---|
| Browser | Nothing. These are the voices your operating system already has. | On your machine | No, always free |
| Microsoft | Nothing. No key, no download. 322 neural voices across 142 locales. | Microsoft's service | Yes |
| Piper | A one-time download per voice, a few megabytes each. Over 100 voices in more than 30 languages. | On your machine | Yes |
| Kokoro | One shared model of about 155 MB, downloaded once for all 28 English voices. | On your machine | Yes |
| Gemini | Your own Google AI API key. 30 expressive voices. | Google's service | Yes |
| OpenAI | Your own OpenAI API key. 13 voices. | OpenAI's service | Yes |
The Browser tab can also carry Chrome's own Google … (Natural) voices. They belong to Chrome's reading mode rather than to your system, so they are offered only once Readalix has quietly tried one and had it answer. Chrome loads that engine the first time its own reading mode reads something aloud, so the voices can be absent just after a restart and appear later in the same session.
Privacy, in one line. Browser, Piper and Kokoro voices are produced on your own machine, so the text never leaves the browser. Microsoft, Gemini and OpenAI are cloud voices: the sentence being read is sent to that provider so it can be spoken. Your API keys stay on the device, are never synced, and are never sent to us. The privacy policy says it in full.
Hear one first
Every voice row carries a small play button. Press it and that voice speaks a sample, so you can pick by ear instead of by name. The sample plays without changing the voice you are set to, and one sample plays at a time.
Downloading a local voice
Piper voices are downloaded one at a time: the row shows the size, and pressing it starts the download and turns into a percentage, then into a Remove button once it is on disk. Kokoro is one model shared by all its voices, so its tab carries a single download control.
Once a local voice is downloaded it needs no network at all, which makes it the one to reach for on a plane or a bad connection.
Adding an API key
- Open Settings, then Languages & voices, then the Voices button on the language you want.
- Choose the Gemini or OpenAI tab.
- Paste your key into the field on that tab. It is checked against the provider before it is saved, so a typo tells you at once rather than at the first read.
A saved key shows as a small chip with a Remove API key button beside it. The key is stored on that device only. It is not synced to your other computers, and it never reaches Readalix.
Choosing the language
The toolbar's Language button decides which language the text is treated as, which in turn decides which voices are offered and how sentences are split. Languages are listed by their own name, one entry per language, and the search box matches the native name, the English name or the country, so "Arabic", "Egypt" and "مصر" all find the same row.
Two ways to make that list yours, both in Settings, Languages & voices:
- Hide what you do not speakThe switch on a language row keeps it out of the toolbar's menu. The row stays in settings, dimmed, so you can bring it back.
- Order them yourselfDrag a row by its grip. That order is what the toolbar's Language menu uses too. Left alone, the list keeps one order and never rearranges itself.
The same page carries the toggle that sets the extension's own interface language, on any row whose language Readalix has been translated into. There are 52 of them.
Which voices highlight exactly
Sentence highlighting is always accurate. Word highlighting depends on whether the voice reports where it is:
- ExactMicrosoft and Kokoro voices report the start of every word, so the highlight lands on the word being spoken.
- ClosePiper, Gemini and OpenAI voices are timed against the real duration of the audio they produced, which keeps the highlight tight.
- EstimatedSome browser voices report nothing, so the highlight is paced from the reading speed and the length of each word. It drifts a little on long sentences.
A voice list says which kind it is on the row itself, so you never have to guess before choosing.