Kuba English
Intro
When one of the Czech Republic’s most popular English teachers, Jakub Čáslava—known online as Kubova English—approached us, his idea sounded both bold and exciting: to clone himself into an AI avatar so people could practice English whenever they wanted.
We jumped straight into the project, and, in just four months, took the idea from a rough sketch all the way to the app stores, delivering a full return on investment in its first month.
Mission
Make English practice fun and stress-free
Many Czech learners understand English passively but struggle when it comes to speaking. Many language learning apps, like Duolingo, teach vocabulary but don’t prepare people for real conversation.
Kuba wanted something different: an app where users could practice speaking with his AI-powered avatar in a private, safe space, while enjoying the same humor his fans know from his Instagram account.
Challenge
From zero to app store in four months
We kicked things off with a design sprint and built a working prototype in just one week. Early user testing showed people were excited about the concept, confirming we were on the right track.
Turning a prototype into a polished app, however, presented a few challenges:
Making voices sound human: We experimented with various settings in ElevenLabs and Kuba’s speech recordings to achieve the most natural-sounding voice.
Keeping conversations flowing: To make interactions feel realistic and engaging, the app needed to respond quickly, stay context-aware, and even throw in a signature Kuba joke every now and then.
Syncing lips with speech: We also had to make sure that the avatar’s mouth movements matched the audio perfectly, creating a lifelike digital twin.
Solution
An AI tutor with personality
After months of design, testing, and iteration, the final app delivered a truly unique experience for Czech learners. From the start, it was clear that this was something entirely new for the local market. It offered:
Multiple AI avatars, each reflecting a different side of Kuba’s personality, with unique teaching styles and voices
Interactive chat for speaking, typing, translations, and feedback
Real-time speech recognition paired with lip-synced avatars
Structured lesson plans for beginners, intermediate, and advanced users
A content library packed with short videos, podcasts, and story-based minigames where users answered questions in real time
Personalized recommendations to track progress and boost confidence
By combining conversation practice, humor, and interactive content, the app quickly struck a chord with users. Within weeks of launch, thousands of users left glowing reviews, and it reached an average rating of 4.9 stars. Development costs were fully recouped in the first month.
Testimonials
“Applifting’s team became our ultimate partners. Thanks to the Design Sprint workshop, we got an early MVP and a clear idea of how to put the app together. We loved the collaboration, energy, and ideas they brought. It was a ride, and absolutely worth it. The reviews speak for themselves!”
Jakub Čáslava
Influencer & Founder
