Step 1 of 6 in When a Spanish version is missing
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Asking for Spanish that isn't there
Lesson 2 Teach Book is written and published in English, but nobody has written a Spanish version yet. A reader asks for it in Spanish.
Each language is a version of its own, and asking for one that doesn't exist finds nothing: not a blank page, and not an error for you to fix, just no Teach Book in Spanish. Anyone asking in English gets the English version as usual.
Try it: compare what each reader gets.
What a reader asking in Spanish gets depends on how they ask: for Spanish only, or for Spanish with English where Spanish is missing. The next step shows the second way.