S. Korean AI tutor outperforms GPT models in Korean language teaching, ETRI says

ETRI develops AI tutor tailored for foreign learners, managing both free conversation and learning progress at the same time

ETRI researcher Lee Woo-jin explains AI learning technology based on smart glasses that enables Korean language study and communication through voice alone. [ETRI]

South Korean researchers have developed an AI teacher that holds free-flowing conversations with learners while tracking their progress according to their Korean proficiency level. In an independent external evaluation, the system recorded a response appropriateness rate of 93.8 percent, surpassing both GPT-4o-mini and GPT-5.1.

The Electronics and Telecommunications Research Institute (ETRI) announced Wednesday that it had developed what it calls a "Korean AI teacher" — an education-focused AI system designed to improve the conversational Korean skills of foreign learners.

The core of the technology is a "topic-guided free conversation" approach. Conventional generative AI can converse freely with learners but has struggled to follow a structured curriculum at the same time.

The ETRI system addresses this by presenting learners with only a conversation topic while internally managing the learning sequence. Even when a learner steers the conversation in a different direction, the AI naturally guides the exchange with questions to ensure the intended learning objectives are met.

To achieve this, the research team applied techniques for tracking conversation progress and preventing repeated questions. The system combines ETRI's own small language models — ranging from 3 billion to 13 billion parameters — with general-purpose AI such as GPT. Familiar expressions are handled by the in-house model, while unfamiliar ones are routed to the general-purpose AI. The design improves response consistency while reducing the amount of learner conversation data transmitted to overseas servers.

ETRI Senior Researcher Choi Hong-seok and researcher Lee Woo-jin explain the AI tutor technology that supports Korean language learning through free conversation with foreign learners. [ETRI]

According to ETRI, a blind evaluation conducted by an external organization late last year brought together 102 participants — including Korean language teachers, foreign learners, and AI and language education specialists — to compare the Korean speaking performance of three AI systems.

Higher response appropriateness and lower conversation error rates indicate better performance, with the assessment limited to Korean speaking education. The ETRI system led on response appropriateness at 93.8 percent, ahead of GPT-4o-mini at 91.0 percent and GPT-5.1 at 90.9 percent.

The ETRI system also recorded the lowest conversation error rate at 18.6 percent, compared with 25.4 percent for GPT-4o-mini and 23.7 percent for GPT-5.1.

The research team is now working to expand the tutor into a comprehensive system covering reading and writing in addition to speaking. A pilot program currently offers situational speaking exercises, free conversation, reading comprehension-based dialogue, and an automated writing assessment feature.

ETRI is also developing a Korean learning platform linked to smart glasses, allowing users to converse with the AI by voice alone — without a keyboard or mouse — while wearing the device. The system lets learners ask questions and receive answers based on their surroundings, enabling natural Korean acquisition in everyday situations.

The institute plans to develop the technology further into a personalized education service that reflects each learner's proficiency level and study history.

"We confirmed the competitiveness of our proprietary Korean education technology through a blind evaluation by an external organization," said Lim Su-jong, head of ETRI's Language Intelligence Research Laboratory. "We will continue to advance it into an AI education technology that Korean learners around the world can trust and use."

nbgkoo@heraldcorp.com