Welsh text-to-speech that gets every word right.
Diffian is a bilingual Welsh and English text-to-speech service for the organisations that serve Wales: councils, health boards, contact centres and transport operators. Our own neural voice and our own engine, built for how Welsh is actually spoken.
Generic speech engines fail in Welsh.
Welsh isn’t English with different words. Real service content mixes two languages in a single sentence, and the big cloud voices weren’t built for it. None of the major vendors will even train a custom voice that speaks Welsh.
Mixed-language sentences
Announcements, IVR menus and service messages switch between Welsh and English constantly. Single-language voices read one of them wrong every time.
Diffian: the language is detected word by word, so each word is read in its own language by one natural voice.
Place names
Llanelli, Pen-y-lan, Aberystwyth, Cwmbrân. English voices mangle Welsh place names, and Welsh speakers notice instantly.
Diffian: a curated lexicon of thousands of Welsh place names, built from national transport data.
Mutations
Welsh words change their first letters with grammar. Caerdydd becomes Gaerdydd or Nghaerdydd depending on context, and engines that only know dictionary forms get real sentences wrong.
Diffian: pronunciation entries cover mutated forms, with per-word overrides where rules fall short.
Hear it for yourself.
Every clip was generated by Bronwen, our own neural voice, on the same engine your service would use. The line underneath each sentence is the engine’s actual phonetic output.
Need a bespoke voice or a full announcement pack? Talk to us.
Our own voice. Our own engine. Built for Welsh from the ground up.
When we found that no cloud vendor could give us a custom voice that speaks Welsh, we trained our own. Bronwen is a neural voice that belongs to us, which means it can belong to your service. No per-character licensing and no vendor lock-in.
Bronwen, a voice you can own
A custom-trained neural voice producing 24 kHz audio, efficient enough to run on ordinary CPU servers. Self-host it on your own infrastructure or consume it as a managed API. Your content never has to leave your estate.
Bilingual by design
Per-word language detection handles code-switching automatically, with explicit control when you need it. One request, one voice, both languages, correctly.
Fine control
An SSML subset covers pauses, prosody, substitutions and exact phoneme overrides, plus Welsh and English number expansion. Your Welsh language officer’s corrections can be applied precisely and regenerated in seconds.
Delivery that fits your hardware
A simple HTTP API for live generation, or pre-generated offline audio bundles for annunciators, queue systems and kiosks. GPS-triggered on-vehicle playback needs no connectivity at all.
Anywhere your organisation speaks, it can speak Welsh well.
Built for the public bodies of Wales, and proven on the hardest case first: public transport announcements at national scale.
Councils & public bodies
Councils, health boards, national parks and museums: tannoy announcements, wayfinding, queue systems and digital services, generated in both languages from a single source, with every place name in your area said properly.
Contact centres & IVR
Telephone services are consistently among the weakest areas in Welsh Language Commissioner compliance testing. Give your IVR menus, queue messages and automated lines a fluent Welsh-first voice, without recruiting for it.
Public transport
The Public Service Vehicles (Accessible Information) Regulations 2023 require audible next-stop announcements, with deadlines from October 2026. Diffian generates complete bilingual announcement sets packaged for standard on-vehicle annunciator hardware.
Built around the rules Welsh public services work to.
Welsh Language Standards
Welsh-first service delivery for public bodies in Wales. Diffian generates Welsh and English from one workflow, with Welsh leading, the way the Standards expect it.
PSV Accessible Information Regulations 2023
Audible and visible route information on local bus services. Our announcement templates and offline bundles were designed for exactly this requirement.
Hear it before you decide.
Tell us what your organisation needs to say in Welsh and we’ll send back your own words in Bronwen’s voice, usually the same day. No commitment, no procurement forms.
Prefer email? hello@diffian.com