Left with nothing, I hear you had literally extremes in forte (6)
I believe the answer is:
loudly
'forte' is the definition.
(I know that forte can be written as loudly)
'left with nothing i hear you had literally extremes' is the wordplay.
'left with' becomes 'l' (common abbreviation. I am not sure about the 'with' bit.).
'nothing' becomes 'O' (looks like zero - 0).
'i hear' indicates a 'sounds like' (homophone) clue.
'had' becomes 'd' (in contractions e.g. 'I'd', 'you'd' etc).
'extremes' means to remove the middle letters.
'literally' with its centre removed is 'ly'.
'you' sounds like 'u'.
'l'+'o'+'u'+'d'+'ly'='LOUDLY'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for loudly that I've seen before include "With relatively high volume" , "With a great deal of volume" , "In a noisy way" , "Resoundingly" .)