The last few years have brought a new kind of high-tech convenience to our devices: Many phones can now translate conversations in real time, without a human translator in the middle. Using the Google Translate app on an Android phone or Apple AirPods Pro 3 connected to an iPhone, it’s possible to overcome language barriers. 

But not every person owns a phone that can support live translation, or has the time or bandwidth to install an app (and maybe commit to a subscription).

T-Mobile wants to remove any obstacles that stand in the way of you talking to someone on a phone call. It has live translation at the network level, so even if you own a basic dumb phone, you can talk to someone who speaks one of over 50 languages with the help of T-Mobile’s network AI agent.

Starting today, T-Mobile is opening up registration for a beta of its upcoming Live Translation call feature, which will begin testing in the spring. It’s open to subscribers of any post-paid T-Mobile plan, such as the Essentials, Experience More, Experience Beyond and Better Value plans.

«We want to make voice cool again,» said John Saw, T-Mobile chief technology officer, citing that its customers make 6 billion international calls per year, and 40% of those people travel internationally. «Live translation is a real breakthrough in innovation by introducing the latest AI models into our voice network.»

Just as it did during the beta of what became the T-Satellite service, T-Mobile has not yet decided which plans will include the live translation calling feature. It also hasn’t decided what, if any, cost there will be. T-Satellite is currently included in the Experience Beyond and Better Value plans and available on other plans as a $10 add-on. It’s also open to customers of other providers for $10 a month.

I haven’t tried T-Mobile’s live translation but I look forward to testing it soon.

How live translation will work

To turn on live translation during a call, the T-Mobile subscriber presses *87* (star-eight-seven-star), which activates the AI agent. Only one participant on the call needs to be a T-Mobile subscriber, and it will also work when the customer is roaming.

T-Mobile says there’s no setup, no voice training and no need to specify which languages to translate. The AI agent detects which languages are being spoken in real time and speaks the translation when a person stops speaking.

The AI agent will also detect whether you’re calling from another country and select a language for the translation. If you call someone in Brazil, it might choose Portuguese, for example. If the person speaks a different language, such as Spanish instead of Brazilian Portuguese, the agent will switch immediately.

Also, the spoken translation will not sound like a robotic voice. «Our AI model can actually clone your voice in another language and preserve the intonation, the emotions and the rhythm as well,» all picked up on the fly, said Saw. He attributes the performance to the low latency inherent in T-Mobile’s 5G Advanced network.

Once activated, the feature doesn’t need to be turned off. If both speakers switch to the same language, the AI agent just stops working as the go-between.

The true test will be the quality of the translations. «We have done a lot of benchmarks for AI-powered translations,» Saw said, «and it matches the accuracy of all the established services.» He said the model is compliant with FCC 2027 captioning guidelines and meets all ADA accessibility standards.

When I asked Saw whether conversations are recorded, even during the beta period, he said that kind of fine-tuning is being done using millions of internal-only test calls. «We don’t listen to customers’ calls, and [the AI models] are not trained on customers’ data,» said Saw, noting that the service meets all FCC guidelines for privacy.

Exactly which AI translation models are being used, or which partner companies are providing them, is something Saw declined to share. He did confirm that T-Mobile is working with several AI companies, but «we’re not going to name them because we love them all the same.»

Saw noted that the way T-Mobile’s network is designed as a platform has the advantage of being able to plug in updated AI translation models, run an upgrade overnight and make it available to hundreds of millions of phones.

Live translation is just the first T-Mobile agentic AI feature

All major mobile providers are applying AI at various levels. AT&T recently announced AI tech for optimizing internet traffic at the home router level, for example, and Verizon is enlisting Google’s AI to improve its customer service experience. T-Mobile itself uses AI to automatically redirect cellular load among towers during emergencies.

Without pointing to specific upcoming strategies, Saw named a few other tasks that AI agents could handle in the future, such as an AI receptionist or AI concierge. Centering the AI technology in the network opens up those possibilities.

So why is the company choosing live translation as the first entry for AI-based, customer-facing network features?

«Live translation is not an easier solution to do,» Saw replied, «but it’s the right pain point to be solving today.»