Answer:
a song
Explanation:
practise a form of singing or calling marked by rapid alternation between the normal voice and falsetto
What did you just ask? No one understands!
solitude-isolation
jocund-happy
Isolation, while being the closest synonym to solitude, has a negative connotation. As if the writer didn't choose to be alone in bliss, but were rather trapped where they were- alone.
Happy is a commonly used word. It makes the writer/author seem elementary in their writing, which wouldn't fit in this poem as it's a high level poem that can be used for scholarly analysis.