Grammar is like a piano because... the parts of speech work together to make literature, and the parts of a piano are put together to help create a beautiful sound.
The noun is like the pianist because the piano was created to be played, and pianists are needed to be front and center to play the music. They are also the most important in creating the music just like how the nouns are the most important words in a sentence.
The verbs are the piano keys on a piano because the keys are the tools that the piano players use just like how verbs explain what the nouns are doing. The piano keys are also a very important part on a piano like how the verbs are very important in a sentence.
The prepositions are like the pedals on a piano because they add details and make the sentence flow like the pedals make the sound smoother and connected.
An adverb is like the fall board because it protects the keys from getting dirty; therefore the fall board can make the keys easier to play like how adverbs make verbs more descriptive or easier to understand.
Interjections are like the sound intensity because the sound the piano makes can be a very soft flowing sound, or it can be a loud pounding sound. This relates to interjections because they can intensify a sentence with a "Wow!" or better explain it with a softened "Well."
The conjunctions come last but are definitely not least. Conjunctions put together a sentence to keep it smooth like the music rack holds the music so no mistakes can happen.