Hamlet’s first speech mainly for his friend (7)

I believe the answer is:
horatio
'his friend' is the definition.
The definition suggests a singular noun which matches the answer.
'hamlet's first speech mainly' is the wordplay.
'hamlet's first' becomes 'h' (1st letter of 'hamlet').
'speech' becomes 'oration' (oration is a kind of speech).
'mainly' means to remove the last letter (virtually or mainly the word, but not all of it).
'oration' with its last letter taken off is 'oratio'.
'h'+'oratio'='HORATIO'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for horatio that I've seen before include "Hamlet''s friend - Nelson" , "part of Hamlet" , "- Nelson, British admiral" , "Shakespearean part" , "Speaker of Good night, sweet prince (Hamlet)" .)
