It may be a tiny girl's reason for not singing (10)
I believe the answer is:
laryngitis
'it may be a tiny girl's reason for not singing' is the definition.
The definition suggests a singular noun which matches the answer.
'it may be a tiny girl's' is the wordplay.
'it may be' is an anagram indicator (I've seen this in other clues).
'a'+'tiny'+'girls'='atinygirls'
'atinygirls' is an anagram of 'LARYNGITIS'.
Can you help me to learn more?
(Other definitions for laryngitis that I've seen before include "Inflammation of the windpipe" , "Sore throat" , "Throat infection" , "Inflammation making it difficult to speak" , "Inflammation of part of throat" .)