To talk with enthusiasm in talk about hard earth is exhausting at first (10)

'to talk with enthusiasm in talk' is the definition.
I know nothing about this answer so I can't judge whether this works.

'hard earth is exhausting at first' is the wordplay.
'hard' becomes 'rhap' (I can't justify this - if you can you should believe this answer much more).
'earth' becomes 'sod' (I've seen this before).
'at first' suggests taking the first letters.
The first letter of 'exhausting' is 'e'.
'rhap'+'sod'+'is'+'e'='RHAPSODISE'

'about' is the link.

Can you help me to learn more?