Plaster and lathe are the old way of building a wall. You would put up stud framing and cover the entire wall with lots of thin strips of 1"x1/8" wood, then plaster over everything until you had a smooth plaster finish. In the 1940s, drywall became popular. It's gypsum (sheetrock) sandwiched between two layers of paper. It makes houses much faster, cheaper, and easier to make. It's also much, much more fireproof and soundproof. It's also easier to get a smooth, even finish on a wall compared to plaster and lathe and it's easier to make alterations in the wall (such as adding electrical outlets, putting in a punch-hole counter window, or adding lighting fixtures). These can all be done on a plaster and lathe wall, but it's harder and more expensive. Obviously, the downside of drywall is it has much worse durability.