By Alex Nicolson
Caitlyn has already touched on this, but I'll add some ideas of my own regarding characters and their particular dialogue.
Perhaps most interestingly, is Biff's name, which is short, harsh, and masculine. It is monosyllabic, and comes out of the mouth with a puff of air, and is onomatopoeia-like for a punching noise. It also rhymes with "if" which is perhaps a metaphor for Biff's character as a whole. His life, at least as Willy sees it, has been a giant wasted "if." What if Biff hadn't flunked math? What if he had gone to UVA? The Ifs roll on and on.
Happy on the other hand, always says things to make people happy. He uses the language of compromise, even telling half-truths and outright lies to keep the illusion of tranquility in the Loman household. Happy almost constantly asks questions, belying his insecurity and also giving his lines a higher, whinier pitch. By never making statements, he never asserts himself, always phrasing things in the less decisive form of a question, asking for the approval of those around him. However, he often uses superlatives, claiming Willy "has the finest eye for color in the business," for example. He constantly exaggerates so that he never speaks his mind plainly, but rather cloaks it all in a sugar coating to keep everyone happy.
In stark contrast to Happy, Linda rarely asks questions, and almost always makes statements and accusations. This gives her a much more decisive, confident sound, and reinforcing her as the stable foundation the family is built on. While she speaks far less than the other characters, when she does speak, it is always a poignant observation straight to the heart of the matter, with no frills or fluff.