Is outspoken before Ella starts to sing (8)

'sing' is the definition.
('sing'->'vocalize' is in my internal thesaurus and 'ize'->'ise')

'is outspoken before ella starts' is the wordplay.
'outspoken' becomes 'vocal' ('vocal' can be a synonym of 'outspoken').
'before' means one lot of letters go next to another.
'starts' says to take the initial letters.
The initial letter of 'ella' is 'e'.
'is' put after 'vocal' is 'vocalis'.
'vocalis'+'e'='VOCALISE'

'to' is the link.