Challenge 3 — Solution

Task: A user wants a lesson built from the full lyrics of a song
currently in the commercial charts. Using L7, explain what CAN and
CANNOT be generated, and why the distinction exists.

What CANNOT be generated: the full song: format - a line-by-line
lesson reproducing the actual lyrics (in the target language, with
transliteration where relevant, alongside the English original). L7 is
explicit that song: may only be used with lyrics that are genuinely
copyright-free - public domain, traditional/folk material, or original
content written specifically for the lesson. A song currently in the
commercial charts is about as far from that as a song can get, so this
request should be flagged rather than proceeded with silently.

What CAN be generated instead: the songvocab: format - a vocabulary-
only extraction. This pulls out individual, noteworthy words from the
song, translated and grouped by part of speech, with NO reproduction
of the lyrics themselves in any form - no line-by-line translation, no
romanized full lines, no quoted lyric fragments even as usage examples
(an original example sentence would be written instead, if one were
needed for a vocab entry).

Why the distinction exists: translating and reproducing a song's own
lyrics line by line - even with vocabulary annotations layered on top
- is still reproducing the copyrighted work, since translation is
itself a derivative work protected the same as the original.
Individual, decontextualized vocabulary words extracted from a song
are different in kind: isolated words and their plain translations
aren't the protected creative expression a song actually consists of -
the specific sequence, phrasing, and arrangement of those words is what
copyright protects, and songvocab: deliberately never reconstructs any
of that.

Notes:
- This mirrors a distinction the site draws elsewhere too (the site's
  own general copyright-quoting rules) - a short, isolated fact or word
  can usually be used safely, while reproducing a substantial, ordered
  piece of someone else's actual creative expression cannot, regardless
  of how it's dressed up (translated, annotated, etc.).
- If there's a real reason to doubt whether a specific song actually is
  public domain or traditional before using the full song: format, L7
  says to ask rather than assume - the responsibility for confirming
  copyright status ultimately sits with whoever requests the lesson,
  but a genuinely doubtful case is still worth raising rather than
  silently trusting.