Singapore's CallBridge Gives Deaf Users a Direct Line to Everyday Services

From unanswered calls to speaking for yourself

Ten deaf users joined CallBridge's initial Singapore pilot and completed 57 calls in its first two weeks. For Alfred Yeo, who has been deaf since age five, the change is personal: a ringing phone can now lead to a conversation instead of a dead end.

Yeo previously could not hear callers, answer a bank officer's questions or resolve a problem through an agency hotline. With the Singapore built app, he can read what the caller says and type an answer that an artificial voice reads aloud. He now uses it to call friends, arrange delivery drop offs and communicate with a driver looking for his pickup point.

CallBridge combines two familiar technologies, speech to text and text to speech, to connect deaf and hard of hearing users with ordinary telephone numbers. The hearing person does not need to install an app or use a special headset. The deaf user reads and types; the other person speaks and listens.

The Singapore Association for the Deaf, also known as SADeaf, estimates that around half a million people in Singapore have some degree of hearing loss. About 5,400 are registered with the association. Those figures show how much larger the population experiencing hearing loss is than the association's registered membership.

Banks, telecommunications companies and government agencies still use phone calls for customer support, verification and urgent assistance. When a service requires a call, someone who cannot hear the conversation may face delays or need another person to speak on their behalf. CallBridge aims to make that contact more direct, giving users greater independence and privacy.

As of November 2, 2025, the Android version is available on Google Play, while the team is targeting a broader app store launch during November. The project has moved from a community hackathon into an accelerator and small pilots, with further work planned on languages, caller identification and hotline staff training.

How a conversation moves between speech and text

An incoming CallBridge call triggers a push notification. The user taps to answer within the app, where the caller's spoken words appear as text in real time. The user then types a response, which the app converts into speech for the caller to hear.

Speech to text turns spoken language into written words. Text to speech performs the reverse task, giving a voice to a written reply. CallBridge handles both directions so that a person who uses text can converse with someone using a standard phone connection.

An outgoing call begins with an automatic introduction. It explains that the recipient is speaking with a deaf person using CallBridge and asks them to allow a little extra time for typed replies. Giving that explanation at the beginning helps the recipient understand the pauses and has reduced confusion and abrupt hang ups.

The app's controls address several practical parts of a call:

• An introduction message sets expectations before the conversation starts.
• Quick replies let users prepare short phrases for common answers.
• A number pad lets users navigate automated call centre menus that require callers to press numbers rather than speak.
• A Singaporean sounding voice, developed through a partnership with ElevenLabs, makes spoken replies sound more familiar.
• Optional typing sounds let the recipient know that the user is preparing an answer.

Quick replies reduce the time needed to answer routine questions. The number pad helps users get through queue systems and verification steps. Together with transcription and spoken responses, these features are intended to make the exchange feel as close to a standard phone conversation as possible.

Why the team built a Singapore service

CallBridge began during the Sparks x Build for Good Community Hackathon, organised by the People's Association and Open Government Products, or OGP. Its developers were responding to a local gap: overseas services with similar aims, including Nagish and InnoCaption, are not available in Singapore.

Availability of such services depends on support for a particular market, connections with telecommunications systems and other service decisions. For many deaf users in Singapore, there was no direct way to make and receive ordinary phone calls independently with both captions and spoken replies.

The project was selected for the Build for Good accelerator, which provided funding, mentorship and access to agencies for pilot tests. Early visits to Deaf Hangouts gave the team opportunities to meet users and understand the barriers they encountered in daily life.

Those conversations influenced how people first learn to use the app, the wording and tone of its opening message, and the choice of voice. Users described services at banks, telecommunications companies and government hotlines that still required telephone contact. Email and text channels could be slow, while an interpreter might be unavailable, costly or unsuitable for a private matter.

What the first users were able to do

The initial pilot included 10 deaf users, among them employees of the Singapore Association for the Deaf. The team reported 57 calls within the first two weeks, with users completing practical tasks through the service.

Yeo's experience shows the range of everyday situations involved. A call can help settle a delivery arrangement, connect with a friend or resolve confusion about a pickup location. Being able to respond himself changes who controls the exchange: he can communicate his own needs without asking another person to make the call.

A participant in the Singapore pilot described the satisfaction of completing a simple errand independently:

I called the bakery and they answered my question, it felt quite accomplishing.

Another pilot participant, describing use of the app in a work setting, spoke about having direct access to the tool:

I do not need to depend on anyone. I can just access this tool without any worries.

The pilots are deliberately small, allowing the team to learn from users while refining the service. The first calls already covered real needs, from obtaining an answer from a business to handling communication at work. Community sessions and small group pilots also help users build confidence before relying on the app for their own conversations.

Why the voice and pauses matter

Early testing revealed that the hearing recipient's reaction could determine whether a call continued. A robotic voice sometimes prompted a hang up. A long silence while the deaf caller typed could have the same result.

The team partnered with ElevenLabs to create a Singaporean sounding voice and refined the introduction message. A more familiar voice reduced early hang ups associated with robotic delivery, while the introduction explained why the conversation might move at a different pace.

Optional keystroke sounds serve a related purpose. They reassure the recipient that an answer is being prepared during a pause. The team also encouraged users to write shorter sentences and use quick replies for common responses, reducing the time between exchanges.

Latency, the delay between an action and its result, remains the toughest technical and human factor. A user needs time to read and type, and network conditions can slow transcription or the delivery of spoken replies. Hearing callers accustomed to rapid conversation may find those gaps uncomfortable.

The app therefore needs both working technology and an understanding recipient. Its voice, introduction and typing sounds help keep people engaged long enough to finish the task. Staff training is intended to make the same pauses easier to manage when users call public services.

Getting names, numbers and menus right

Names, reference codes and numbers require particular care because automated transcription can miss them. A caller may need to share a sequence of digits or spell a name, and the text on the user's screen needs to convey that information accurately.

The team has worked to improve the handling of names, spelling and numeric sequences. Shorter sentences and prepared replies can also shorten pauses and reduce opportunities for errors during an exchange.

Automated telephone menus create another practical requirement. Many call centres ask customers to press a number to choose a department or continue through a verification process. CallBridge's number pad supports these systems, including menus that do not accept spoken input.

Some users need a walkthrough before these controls become familiar. The team has been holding community sessions and small group pilots to explain when to use quick replies, how to set the introduction message and how to navigate call centre menus.

Those details matter because reaching a person can involve several steps before the main conversation begins. The app must help the user move through the telephone system as well as read and answer the person who eventually picks up.

Preparing hotline staff to take the calls

Public agency staff have taken part in simulated calls so frontline teams can practise responding to CallBridge users. Pilot calls with helpline staff have helped the developers identify where training is needed.

A staff member who recognises the opening message can allow time for typing instead of assuming that the caller has stopped responding. Familiarity with the process can reduce confusion and make the exchange faster for both people.

The team plans to expand this work into certification for hotline staff likely to receive CallBridge calls. A planned second phase partnership with the People's Association would train and certify helpline staff, extending the work beyond individual product tests.

Further hotline trials are planned with agencies and services including NAVH and Mindline. The team is also discussing outreach with SADeaf to reach more members and exploring partnerships with telecommunications companies on plans tailored to deaf users.

Wider adoption by agencies and businesses is part of improving call success. The caller's app can explain the process, while staff who have practised receiving these calls can respond with the patience and familiarity needed to complete them.

Availability and the next development steps

CallBridge began as a private pilot accessed through a sign up link. By November 2, it was rolling out on app stores, with its Android version available on Google Play. Performance adjustments and interface refinements were already being released.

The team's sequence of development and planned expansion is:

• The project began at the Sparks x Build for Good Community Hackathon and was selected for the Build for Good accelerator.
• An initial private pilot brought in 10 deaf users, who completed 57 calls during its first two weeks.
• By November 2, 2025, the Android app was available on Google Play and the team was targeting a broader launch during November.
• Planned work includes additional languages, Singpass verification, further hotline trials and a second phase of staff training with the People's Association.

No specific day was given for the broader November launch or for the other planned additions. Interested users can join the waitlist and find more information through the CallBridge sign up website.

The app currently supports English. More languages are on the roadmap so people can communicate in the language that suits their situation, including in multilingual households and with businesses serving customers in different languages.

Planned Singpass verification is intended to build trust around caller identity. Alongside language support, hotline trials and telecommunications partnerships, it is part of the team's effort to make the service useful across more everyday interactions.

How it fits alongside other ways to communicate

Text messages, email and chat already help deaf and hard of hearing people contact services. Their usefulness depends on whether a business or agency accepts those channels for the task at hand. Many essential services still ask customers to call, and written channels can involve a longer wait.

A family member or friend can place a call, but that introduces another person into a conversation that may involve sensitive information. Waiting for an interpreter may also be impractical for an urgent matter or a quick check that would otherwise take a minute.

Video relay services use a sign language interpreter to connect the two parties through video. That approach remains useful in many countries, but it requires an interpreter to be available and brings a third person into matters such as banking. Other captioning tools help with meetings without connecting users to ordinary telephone lines.

CallBridge takes a different route by letting the deaf user call any standard phone number and supply their own replies. The exchange stays between the two participants, with the app turning the user's typed words into a voice. Direct contact and independence are its central advantages.

Singapore's estimated half a million residents with some hearing loss represent a substantial need for accessible communication. Being able to call a clinic, bank or government hotline without asking someone else to speak can make daily tasks easier and more private. CallBridge's development, from community conversations to testing with users and frontline staff, shows how those practical needs have shaped the product.

Key Points

• CallBridge converts a caller's speech into text and a deaf user's typed replies into speech, supporting incoming and outgoing calls.
• Its first Singapore pilot involved 10 deaf users and 57 calls in two weeks.
• SADeaf estimates around half a million people in Singapore have some hearing loss, with about 5,400 registered with the association.
• An introduction message, a Singaporean sounding voice, quick replies and optional typing sounds help keep conversations moving.
• A number pad supports automated telephone menus, while further work targets names, spelling and numbers.
• The Android version was available on Google Play as of November 2, 2025, with a broader launch targeted for November.
• English is supported, with additional languages, Singpass verification, hotline trials and staff certification planned.