I am a high school English teacher and I have enjoyed diagraming sentences for many reasons: My students seem to enjoy it as a puzzle. In order to understand where a word goes, one must first understand what it does in a sentence. The logic of the processes permits it to become in a sense mathematical, since more issues may be added to previous diagrams. The question ultimately seems to be: why teach grammar at all? Grammar is usually taught for the sake of establishing rules and regulations of proper writing--diagrams explain these rules and help students understand how sentences generate meaning. One might then ask very subtle grammatical questions when reading poetry: Why, for example, does Shakespeare use the singular form of the verb in the "Tomorrow, and Tomorrow and Tomorrow..." speech? Why are there three ostensible subjects followed by a singular verb "creeps"? How does understanding this question help us understand what Shakespeare is saying--how, in other words, does grammatical knowledge help us understand the philosophical implications of his usage? Similarly, in the sonnet "When, in disgrage with Fortune and men's eyes...." why is there a comma after "when"? I have seen this sonnet published without the comma, which is of course all wrong and changes the meaning? The question one might ask a class which has been thoroughly versed in grammatical issues is: What meanings are changed by eliminating the comma? The issue ultimately for me has not been diagraming in itself, but rather the treasures of philosophical issues that are unearthed in understanding how words for sentences to generate meaning. RonT