Lecture, oration, redress.
address
Another word for a formal speech is an oration or a discourse.
Formal is an adjective.
stutter stammer
The starting word of a speech is the introduction. Many people begin their speech with a greeting to the audience and distinguished guests.
I'm not sure whether you are asking about "formal" (which is an adjective) or "in" (which is a preposition).
a harfo
dude. gidday how are ya
A four letter word starting with the letter a is able.
Formal
The word whomever is a pronoun. It is the formal usage of whoever.
H is a letter, not a word. To be a part of speech, it needs to be a word.
Waterhose is a nine letter word starting with the letter W!