AI subtitle glasses bring Korean musicals closer to global audiences

A scene from the musical "Kinky Boots" / Courtesy of CJ ENM

For years, Korea’s booming musical theater scene has drawn foreign visitors with its polished productions and emotionally charged performances. Yet for many non-Korean speakers, the experience often came with a degree of frustration. The music and choreography landed, but the story itself remained somewhat out of reach.

That gap is now beginning to narrow. At several theaters in Seoul, subtitle glasses powered by artificial intelligence (AI) have entered commercial use for general audiences, marking the first time the technology has been made available at major Korean theaters.

One such example is the ongoing run of “Kinky Boots” at Charlotte Theater in Seoul’s Songpa District, which shows how the subtitle glasses enable international audiences to follow Korean dialogue without losing sight of the stage.

The musical, one of entertainment powerhouse CJ ENM's flagship global co-production projects, is based on the success story of a struggling shoe factory in England. Facing bankruptcy, the factory survives by reinventing itself through the production of flashy, unconventional boots for drag performers.

The musical’s themes of inclusion, self-acceptance and reinvention are driven as much by its dialogue as by its songs, making comprehension especially important for first-time viewers.

The official poster for the artificial intelligence-powered subtitle glasses available for the Korean production of "Kinky Boots" at the Charlotte Theater / Courtesy of Lotte Cultureworks

For most Korean musicals, subtitles have historically appeared on large monitors at the sides of the stage, mainly to provide Korean captions for productions performed in foreign languages. Korean-language shows rarely offer English subtitles at all, aside from a handful of state-funded productions. This, therefore, required audiences to repeatedly shift their gaze away from the performers, resulting in a fragmented viewing experience.

By contrast, the subtitle glasses offer a simpler alternative. Much like borrowing 3D glasses at a cinema, audience members rent the devices from a dedicated counter, and when worn, captions appear directly on the lenses rather than on a separate screen.

Some Broadway shows, which rely much more on international visitors than Korean productions, offer caption services mainly through mobile applications such as GalaPro, but looking between the stage and your smartphone can be distracting as well.

The glasses currently offer subtitles in English, Japanese and Chinese, both simplified and traditional, with more languages set to be made available in the future. A Korean subtitle option is also available, making the service useful not only for foreign visitors but also for audience members with hearing impairments. The rental fee is 15,000 won ($10.15) per performance.

The service is currently in use across multiple shows, including the long-running Daehangno play “Finding Kim Jong-wook,” as well as musicals such as “Rachmaninoff,” “Vamp x Hunter,” “Amadeus,” “Behind the Moon” and “Man in Hanbok.”

Artificial intelligence-powered subtitle glasses / Korea Times photo by Pyo Kyung-min

Alyssa Chen, a journalist dispatched to The Korea Times by the Hong Kong-based English-language newspaper South China Morning Post, tested the glasses during a performance of "Kinky Boots." For her, the device marked a turning point in how foreign audiences can engage with Korean musicals.

“For foreign audiences in Korea, language barriers have long hindered the full enjoyment of musicals,” she said. “But with the debut of AI-powered subtitle glasses, that challenge is fading.”

The device arrives in a compact kit that includes a manual, a cleaning wipe, a power bank and a smartphone used for customization. The rented smartphone comes preloaded with a dedicated app used to adjust the glasses’ settings. In the future, users will be able to download the app onto their own smartphones instead.

“Viewers can easily adjust font size, brightness and caption placement,” she said, although the placement is limited to three preset positions. Even so, she found the flexibility effective, saying it “ensures that the subtitles feel integrated into the performance rather than a distraction.”

Chen described the physical design of the glasses as “unobtrusive,” noting that they are well-balanced and are light enough to wear throughout a full performance. She added that the brightness of the captions did not overpower the stage lighting and allowed performers and choreography to remain visually dominant. Overall, the effect felt “almost as natural as watching with the naked eye.”

On translation accuracy and timing, Chen noted the system occasionally missed softly delivered lines or briefly mixed captions during rapid exchanges, but said the errors were minor and did not significantly disrupt her understanding of the performance.

A simulated view through artificial intelligence-powered subtitle glasses shows translated dialogue projected onto the lens during a musical performance. Courtesy of XPERTINC

The technology behind the glasses is developed by XPERTINC, a Seoul-based firm founded in 2019. The company combines its proprietary AI speech-to-text engine with smart glass hardware. According to the company, the system has achieved "98 percent speech recognition accuracy" under nationally certified testing standards, with audio converted to text in under 0.3 seconds.

Jung You-seop, senior managing director at XPERTINC, told The Korea Times that the technology is steadily gaining traction among foreign audiences interested in Korean musicals.

“At the moment, we prepare about 40 to 50 pairs per performance,” Jung said. “For productions attracting a large number of international viewers, like the currently running 'Man in Hanbok,' we sometimes see 15 to 20 devices rented out in a single night.”

Designed to remain unobtrusive during live performances, the system operates by preloading the script into the program, allowing the glasses to generate captions through real-time AI speech recognition during the performance. However, since it relies on preloaded dialogue, it can't process unscripted or improvised lines.

“These subtitle glasses were developed by our company with the goal of creating social value and this approach is, to our knowledge, the first of its kind in the world,” Jung said.

Jung added that broader adoption will ultimately determine the project's long-term impact.

“If this becomes more widely known and helps foreign audiences access Korean content more easily, that alone would make the effort worthwhile,” Jung said.

A scene from the musical "Kinky Boots" / Courtesy of CJ ENM

There are still practical considerations. While the glasses can be worn over prescription eyewear, the layered fit may become uncomfortable during longer performances. For those who normally wear glasses, Chen recommends contact lenses for a smoother experience.

For her, however, the emotional impact of the technology outweighed these small inconveniences.

During the musical's famous final number “Raise You Up,” she found herself focused not on decoding a foreign language but on the performers’ voices and expressions. Understanding every line allowed the song’s message of solidarity and pride to land with full force.

“What truly stood out was how the glasses helped deepen my emotional connection to the performance,” she said.

Alyssa Chen, a reporter with the South China Morning Post, contributed to this article.