Is there an open-source set of topics and vocabulary for making a language tutorial?

There could be errors in this since I'm not very familiar with it.

Fluent Forever's approach looks like it's adaptable to any language. Fluent Forever is a language learning app you can buy. Their approach involves the learning taking steps to make their own flashcards and get materials, so I think it's adaptable for new languages.

I'm going to highlight specifically their vocabulary learning approach because I think that's usable to conlangers. They provide a 625 word core vocabulary of easily pictured frequent words that you can copy from their website. It might not be exactly 625 words in your language, because you might divide up the semantic space differently. For each of these words, you can make multiple flashcards with example pictures. The learner makes their own flashcards by selecting pictures and example sentences. If you don't have the app, they recommend you create your flashcards in random order on the the Anki flashcard program, and then it will quiz you with spaced repetition.

They also have a method of teaching phonetics through recordings of minimum pairs. That could be worthwhile if you have the time to make many recordings.

Their approach to teaching grammar is with naturally occurring example sentences and just enough translations to give people their bearings. Since there aren't naturally occurring sentences in your language, you'll have to come up with your own. My opinion is that you can't learn a grammar solely from a small number of example sentences.

I found a great blog post called Avoiding the "Boing" by author and conlanger E.M. Epps, in which she laid out a lot of information on conlanging that's helpful for new and experienced conlangers. One resource she recommends for vocabulary is the McGuffey readers. These are books that were used to teach English-speaking children to read. They're numerically ordered by difficulty, so that you can start with the Primer or start with the "New First Reader", and that's likely to be plenty of content for a lot of conlangs.

A few downsides to this:

1. It tries to focus on a small number of English letters at a time, so the vocabulary choices are affected by English. Solution: Don't follow this slavishly.
2. The subject material is intended for children, so adults may find it hard to connect. Solution: For a more adult vocabulary, replace "milk" with "coffee" and replace "play" with "awkward smalltalk".
3. It was originally intended for people who are already fluent in the language, so it doesn't directly teach the grammar. Solution: You can call attention to new grammar points as they come up. The primer does some of this for you in that it takes multiple pages before plural nouns, possessives, and conjugated verbs are introduced.

One place to start is the Universal Language Dictionary. ULD Version 2.7 is listed on the Frath Wiki. ULD Version 3 is available in Google Sheet form.

The Universal Language Dictionary is a list of concepts that can be represented as a word in a conlang. Each concept belongs to a category such as "Function words", "Clothing", and "Foodstuffs". Each concept also has a level between 0 and 3.

To design your course, you can sort these by level, and then sort each level by categories as you wish. Level 0 has only 30 words and it make sense to do them in this order:

• Function Word
• Adpositions
• Numerals
• Degree

The other categories have dozens of categories and 100-1000 words in them, so they take more work to sort, but at least it's a start.

You'll probably want to deviate from this pattern some. I'd want to introduce some nouns and greetings before I get into function terms. I'd also introduce food items as soon as I introduce the word eat.

You'll need to introduce some terms that aren't on the list, and of course other grammar. There's no word for "the" or "a" on the list because those are not considered universal.

Some background information can be found here. This includes the relevant license for version 2.7 of the ULD:

Copyright 1992-1995 by Richard K. Harrison. All rights reserved. Permission is hereby granted for unrestricted use of these files by any individual for his/her own pleasure, private research, personal communication, etc. Use of these files by any government agency, business entity, educational institution, or any other organization requires permission.

I would guess that other versions of it have similar permissions, but I can't guarantee it.