About SAUNA
So that foreign languages don’t stand in someone’s way
From why you need to learn a foreign language yourself to how you’ll remember and keep that long journey. We talk about the standards for creating SAUNA.
Super Salt Story
Becoming a presence like salt in the world
Connection of Two Names
When sweat dries, it becomes salt
A sauna is a place of effort, and salt is the reward left behind. The sweat learners shed doesn’t vanish into thin air. It gradually solidifies into the power to recall words, the sense to correct sentences, and the confidence to open your mouth.
First, we want to tell you this.
It’s not because you’re not good enough.
Why in the AI era
In the AI era, why learn a foreign language?
Feel the Texture of Culture
AI can translate the words, but it can’t carry over the atmosphere and texture within them.
The moment you meet face to face—without a device
Eventually, the moment comes when you have to open your mouth yourself.
The Basics for Using AI Properly
Someone who knows whether the translation is correct is someone who knows that language.
Experiencing My Own Growth
Only the sweat you’ve shed yourself becomes fully yours.
For whom
Who is this service for?
Learning Connected as One
Four Ways to Learn
Word
Even if it’s wrong, there’s nothing to lose. It means we’ll get another chance to meet.
- We don’t throw both meanings of “school”—a place of learning and a school of thought—at you at once. We start with the one you need right now.
- Read, listen, write, and speak. We’ll help you build these four skills separately.
- The words you’ll review today—we’ll pick them for you. Give us 5 minutes.
Grammar
Don’t memorize grammar. We’ll help you switch to the body’s sensations that react the moment you see it.
- A new example comes up every time. So you can’t just memorize it to get it right.
- Start with the basics—one layer at a time. You don’t learn everything at once.
- Memorized words become grammar examples, and learned grammar brings words to life.
Diary
If you write in a foreign language, AI will fix it and cheer you on.
- If you feel stuck, start with “What did you do today?” We’ll show you examples that include the vocabulary and grammar you learned.
- Your diary entry from this day a year ago, side by side — you can feel your growth, even without tests.
- Write a letter to your future self, a few years from now. When that day comes, let’s open it together.
SelfCall
When the phone rings, pick up. The person in the story calls you.
- The words and grammar you memorized today become the lines of your call, just as they are.
- We don’t judge by score. We’ll show the original lines alongside your voice.
- The more you repeat the same scene, the faster—your body remembers it, even without subtitles.
Word
Memorized Phrases
Grammar
Ingrained structure
Diary
A Sentence for My Day
SelfCall
Conversation spoken out loud
The four services don’t work in isolation. Memorized words become diary entries, then phone conversation lines—and mistakes in your diary turn into review again. AI polishes what you write and say yourself—examples, grammar, diary entries, and calls.
How to Remember the Sweat You Shed
How to Remember the Sweat You Shed
Brings it back when you forget
Just when you’re about to forget, we’ll pick only what you’ve forgotten and bring it back for you.
Shows accumulated progress
We show you changes you couldn’t see on your own.
Celebrates with you
In meaningful moments, we’ll celebrate with you.
A Return That Isn’t in Vain
Review you didn’t do today won’t disappear. Let’s meet again tomorrow and fill it in together.
Rediscover Forgotten Words
It’s okay if you forget words you once learned. Meet them again as “forgotten words,” and this time, help them stay longer.
My Sweat Map
A record that captures every drop of sweat at a glance
Your daily traces don’t disappear—they remain as patterns.
Learning as a habit
We record your consistency and honestly reward your contributions.
Consistency, as a rating
You can’t increase it with payment or luck. Only the learning you actually follow through on changes the density at the habit level.
Get back what you sweat for
Ad revenue generated from free learning is collected in the Reward Pool and returned to people who keep learning and contributing.
Travel: the final reward
Traveling to the region of your learning language and using it firsthand — offered to some as an opportunity.
Habit Level
As a crystal grows, your consistency shines through
Bronze
Silver
Gold
Platinum
Sapphire
Ruby
DiamondThis level can’t be raised with an external payment. Only learning you’ve actually kept up changes the crystal’s density.
Reward Graphics
Giving back is remembered not just in numbers, but in scenes
Milestones and the ad revenue given back to learners are shown not with gambling-style effects, but as “scenes where the sweat you’ve shed remains.”
- Gem crystals stand for rewards and premium achievements
- Salt crystals never disappear—effort that endures
- Warm light brings the joy of milestones
Evidence-based learning
Not feelings—evidence. Put people first, not features.
Forgetting Curve Review
Instead of repeating mindlessly, you revisit only what you need at the moment when forgetting is more likely.
Habit Science
We design a rhythm that continues even after you take a break—without turning streaks into pressure.
International CEFR Standard
From A1 to C2, we align learning levels and content difficulty to international standards.
Quantitative evidence data
Based on frequency, difficulty, and usage data, we choose the words and sentences you need right now.
CEFR Level Badge
Growth made clearer by international standards
A1
A2
B1
B2
C1
C2From A1 to C2, level labels are organized based on international standards and learning evidence—not guesswork.
Brand Story
Brand Story
The language platform that remembers your effort
A place that removes impurities that turn foreign languages into life’s obstacles
Welcome
It’s okay to drop by after a long time. Haru always welcomes you with even more warmth.
Support
Not talkative. Haru watches quietly, then speaks when it matters most.
Joy
Haru doesn’t say “Good job.” Haru says, “You did it.”
Peace of Mind
It’s okay. Just getting back now is enough for us to continue.
Awe
Even small progress doesn’t slip past Haru—it’s quietly noticed.
Waiting
If you open the door again, Haru will be waiting right there.
Global Vision
This is not a translation of an app for Korean users. We separated the UI, language data, and level system from the ground up based on global standards, preserving the differences across each language and region.
Trust and Responsibility
Users decide how much of their learning records are shared, and for minors we apply more conservative default settings. We don’t hide pricing, rewards, or cancellation criteria, and we don’t trap records to prevent people from leaving.
Privacy
You always decide who can see your records. By default, it’s close to “Only me.”
Transparent Operations
Price changes are announced first, with the reason and timing, and canceling stays just as clear and accessible as signing up.
Honest Rewards
There’s nothing you get by luck. It’s exactly as much as the sweat you’ve shed.