Different bugs need all kinds of different skills! Mostly perl, but some HTML, CSS, Javascript, etc. There's projects of every skill range, from "help I have no idea what I'm doing" to "I am a perl guru". The Getting Started wiki category explains how to get started in DW dev, especially Dev Getting Started and Dreamhack Getting Started (Dreamhacks are our free hosted development environments.) If you get stuck, dw_dev_training is the place to go, where friendly people will answer all your questions.