Welsh announcements will be available in over 170 railway stations by the end of March, according to Transport for Wales.
In July of last year, a report on behalf of the Welsh Language Commisioner stated that Welsh ministers were breaking the law by not ensuring that Welsh services were provided on Transport for Wales trains.
The new service was trialled in Porthmadog, Trefforest Estate, Skewen, Hengoed and Pontyclun at the end of last year.
Amazon and IVONA are the owners of the new technology, known as Geraint, which can provide Welsh language travel announcements and notice of last minute changes.
There are 222 railway stations in Wales. TfW say only a quarter of these had a system that worked in Welsh. The rest had an old text-to-speech system that had trouble pronouncing Welsh.
A spokesperson for the Welsh Language Commissioner said: "The lack of Welsh audio announcements in stations and trains was among the complaints in our investigation of Transport for Wales' Welsh language services.
"A number of other complaints were part of the commisioner's investigation.
"We are now in the appeal phase, when Welsh Ministers can appeal against our final ajudication. We can not make any further comment until the end of that period."
Gweirydd Davies, Head of Welsh Strategy at Transport for Wales, said: "Creating a bilingual transport system is a priority for us at TfW and we are working with the Commisioner's Office to ensure we achieve our aims.
"'Geraint' will make a positive difference for our Welsh-speaking customers.
"The old technology was not fit for purpose with regard to Welsh, so we had to find a new solution and develop it ourselves.
"It is a step in the right direction toward making our network bilingual and we look forward to similar developments in our on-board announcement systems."
