Spoken sentence provides word for ‘herb’ (5)
I believe the answer is:
thyme
'for herb' is the definition.
(thyme is a kind of herb)
'spoken sentence' is the wordplay.
'spoken' indicates a 'sounds like' (homophone) clue.
'sentence' becomes 'time' (a prison sentence).
'time' is a homophone of 'THYME'.
'provides word' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for thyme that I've seen before include "Sweet-smelling herb of the mint family" , "Herb with fragrant leaves - parsley, sage, rosemary and . . . . ." , "Leaves used as seasoning" , "Common herb" , "Aromatic culinary herb; sounds like occasion" .)