A word is a part of speech, not a sentence like the one in your example.
"That'll" is not a part of speech at all; it is a contraction for "that will", in which "that" is a pronoun and "will" an auxiliary verb.
Brother is a noun.
Ragged describes sweater, so it would be an adjective in this sentence.
The part of speech depends on how the word is used. See the examples below.
They spoiled the surprise. spoiled = verb
He threw out the spoiled meat. spoiled = adjective
It's a prepositional phrase.
On the mountain top is a preposition phrase, not a part of speech.
They'd is a contraction of two parts of speech. They is a pronoun; would is a modal verb.
Yes; both the song itself and (separately) the sound recording are protected.
The word "I" is a pronoun.
PREPOSITION
Can be a conjunction, as in he stumbled but did not fall'. Can also be a preposition as in 'we were never anything but poor.' Can be an adverb as in 'but a shadow of his former self'. Can be a noun as in 'no buts, just leave'