David Solomon ran Goldman Sachs and moonlighted as DJ D-Sol. Steve Wozniak co-founded Apple and then quietly spent years teaching elementary school.

It turns out, the day job rarely tells the whole story.

Alongside my professional life, I have a remarkably unglamorous hobby: tinkering with education software, especially language apps. I have been at it since the 1990s.

And every single one of them has the same flaw.

The Problem Nobody Was Solving

Vocabulary apps are almost universally designed for the same person: a tourist. Someone who wants to order coffee, ask for directions, and survive a weekend in Lisbon without embarrassing themselves.

That person is not me. And if you are an expat or an international professional, it is probably not you either.

I have been looking at vocabulary apps for over thirty years. They teach you "the apple is red" and "where is the train station?" They do not teach you the word your landlord just used about your boiler. They do not help you understand the clause in your employment contract that everyone else at the table seemed to find perfectly clear. They do not give you the vocabulary to sound like yourself in a language that is not your first one.

People who speak foreign languages rather well — but have not felt real progress in quite some time — know exactly what I mean. You are not a beginner. You are not struggling with grammar. You just keep hitting walls made of words you do not yet have.

Six Months, One Very Understanding Wife

So, six months ago, I decided to use my free time to build the vocabulary app I had always wished existed.

The app is called Vokabulo. Not a breathtakingly inventive name, I admit, but the .com was available, which in 2026 feels close enough to divine endorsement.

I built it for myself. But it turned out to be especially useful for expats and international professionals — people who are past the beginner stage, who live and work in a foreign language every day, and who need personalized vocabulary rather than games about coloured fruit.

The Honest Part About Money

I did consider making Vokabulo free. Unfortunately, the LLM providers that power Vokabulo have not yet discovered the joys of philanthropy, and I am not especially optimistic that their future IPO roadshows will change that.

So yes, Vokabulo costs money — though less than an espresso a week. But you can try it out as long as you like, subject to some limitations.

Why This Matters

Building Vokabulo gave me a much deeper, hands-on understanding of what AI can actually do for language learning — as opposed to what the marketing claims it can do. The answer, it turns out, is quite a lot, provided you give it the right job to do.

The right job is not replacing a teacher or simulating a conversation partner or gamifying your morning commute. The right job is catching the specific words you encounter in your actual life, understanding them in context, and making sure you remember them.

That is what Vokabulo does.

The Best Possible Outcome

This is a personal side project. I built it because I needed it. The best possible outcome would be discovering that it is useful to other people too.

Because expats and professionals who use a foreign language every day need personalized vocabulary, not games.

I am aware that becoming a DJ would have been the cooler option. But building a vocabulary app seemed, on balance, slightly less hazardous for everyone involved.

Ready to build a vocabulary that actually fits your life? Try Vokabulo — the app built for people who live in a foreign language.