When we asked early learners when they study, the most common answer was "on the way to work". Many of them commute for an hour or more in a busy city, on a bus or a train, often with a patchy mobile connection. Reading a lesson full of diagrams on a phone in a moving bus is hard. Listening is easy.
So every Kolom lesson has a companion episode. Two hosts talk the lesson through: Nadia, a senior engineer at Mangrove Market, and Imran, a product manager there. Nadia explains with everyday pictures. Imran asks the questions a listener would ask, and now and then he makes a reasonable wrong guess that Nadia corrects. That is how you learn the trap without falling into it yourself.
A companion, not a recording of the page
An episode is not the lesson read aloud. It keeps the analogy, the one or two ideas that matter most, a story about what goes wrong, and what the Build-it section does, told in words instead of code. Someone listening with their eyes closed should understand the core idea and remember the trap. Someone who glances at the screen should see the diagram the hosts are talking about.
That last part is the feature we like most. When the lesson is open and "Follow along" is on, the page scrolls to each diagram as the hosts mention it, and the line being spoken is highlighted in the transcript. If you can see the screen, you get the picture. If you cannot, the hosts describe it ("picture a phone, a server and a database, left to right").
Your phone does the talking
The episodes play with the speech voices already on your device, so there is nothing to download and an episode costs almost no data. The player picks two different English voices for the two hosts and remembers your choice. If your device has only one voice, it changes the pitch so you can still tell the hosts apart.
A few things we learned along the way:
- Speech engines read symbols badly. Episodes never contain code, URLs or symbols such as underscores or arrows. Numbers are written the way a person says them: "p ninety-nine", "about four page reads".
- Phones pause speech when the screen locks. The player asks the browser to keep the screen on while you listen, and you can turn that off in its settings.
- Short lines work better. Each line is one idea. That makes it easy to skip back one line when a bus horn drowns out a sentence.
The player sits at the bottom of every page, so it keeps playing while you move around the site, and it starts the next episode in the course when one ends. Your place is saved, and finishing an episode counts toward your streak.
Try it on the caching lesson, or open the podcast page to see every episode by course.