Sound, becasue I still don't know what a line is

Of all teh chapters I have read thus far of Mary Olivers' A Poetry Handbook, teh most intersting to me by far has been the chapter on sound. It was the chapter that was easiest to understand, and which made the most sense, unlike the chapter on lines. If ever a chapter would give one aheadache, it was certainly that one.
When she compared the meaning of a rock vs. stone, it made perfect sense. In my mind they are two different thing. But what intriguied me most was hos she broke down the different aspects of sound in an understandable way. then at the end, she came back to the comparison of rock and stone, and I understood not only that they were different things, but why I perceive them as different things when they are so similar.
I had no idea that there were so many types of letters. To me there were only vowels and consonants, and y and w were never vowels...ever. It was incredible to see how the different "families of sound," semivowels, mutes, aspirates, and consonants etc. work together to create certain words which have certain meanings because of hte placement of the letters. For instance, liquids create a soft sound, and when used at the end of a word have a soothing effect. The complete opposite is true for consonants, which "stop the breath," and add a hardness to the meaning.
In teh last few pages of hte chapter, her dissection of Frosts's " Stopping by teh Woods on a Snowy Evening," allows her to show how all teh different types of letters work together to craete the mood and meaning of hte poem. She earned my respect when, at the end, she finally owned up to teh fact that nat all poets sit down and firgure this all out before writing, adn that each word many not be put there after many hours of forethought as to how the sound would affect the meaning. Yet I understand that this knowledge of sound comes naturally to good poets, and it is something that may appear in a lot of poems without much forethought, but it present nonetheless.