Spanish course: exercises that follow the lesson I watched

Context

I’m learning Spanish from an 82-video series on YouTube. I have Palabra for vocabulary, but nothing to practise the lessons themselves. Once I finished a video, the topic slipped away.

After the first 10 lessons I wrote to Claude Code what I wanted: a short explanation and fill-in and multiple-choice exercises for each lesson, with the English meaning on hover. The focus: verb conjugation, articles and pronouns. No past tense until the present tense has settled.

The problem: the exercises should teach what the lesson taught

Ready-made exercise sites follow their own order. On one site the fifth topic can be the past tense; in my series the past tense starts at lesson 61. The exercises shouldn’t be a step ahead of or behind what the teacher has covered so far, and they should reuse his words and examples.

So we decided to write the content from the videos themselves, not from their titles.

What I built

1. Lessons from transcripts

Claude first pulled the 82 titles of the playlist and set aside the homework checks and Q&A videos, leaving 70 numbered lessons. Then it downloaded the automatic Turkish subtitles of the 10 lessons I had watched (text only, not the videos) and read them: about 27,000 words.

The explanations came from there. The sentences the teacher gave as homework are in the exercises. His comparison of usted with old Turkish “zatıaliniz” is in the explanation. Irregular verbs are taught in the same four groups he uses.

One decision was Claude’s suggestion: all 70 lessons stay in the list, but content is written only for the lessons I’ve watched. Writing the whole series up front would have made it impossible to adjust to where I get stuck.

2. Locks

Lessons open in playlist order. A lesson is finished when two things are true: I scored at least 80% on a set and I ticked “I watched the video”. The exercises alone don’t pass a lesson, so I can’t skip the video.

Each lesson has three tabs: Explanation, Exercises and Completed exercises. Every checked attempt is saved with its answers.

3. Exercise generator

“Generate new exercises” doesn’t call an AI. The app has a dictionary, 33 verbs and the conjugation rules built in. Sentences are built from these and the answer is computed by rule. That way a beginner never gets a wrong question, and there’s no API key or cost.

About 70% of each new set comes from the current lesson and 30% from earlier ones. A lesson 10 set also has the pronouns from lesson 3 and the articles from lesson 5. For irregular verbs the wrong options are picked on purpose: “puedemos” instead of “podemos”, “conoco” instead of “conozco”, the most common mistakes.

4. Meaning on hover

Every Spanish word in the explanations and exercises has a dotted underline. Hovering shows the English; for a verb form it also shows who does it (“quieres → you want · querer”). In test questions, if the meaning would give the answer away, the word stays plain until the answers are checked.

An answer missing only an accent mark counts as correct but is marked in yellow: “adios” passes, with “adiós” shown underneath.

5. Release

I study Spanish through English, so the interface is in English too, always in a light theme. The code is plain HTML, CSS and JavaScript, with no libraries. It lives as a folder in my portfolio repo and is published as a separate Worker on Cloudflare Workers at spanish-course.omertataroglu.com. There’s no account; progress is stored in the browser itself, with backup and restore at the bottom left.

Result

I wrote the message on 18 October 2026, and the first 10 lessons were ready the same day. For new lessons I just tell Claude “I watched lesson 11”: a small tool in the folder downloads the subtitles, and Claude reads the transcript and adds the lesson.

Next up is ser and estar. I’ll get to the past tense at lesson 61; until then every sentence in the app is in the present tense.