Students with upper body motor impairments, such as cerebral palsy, multiple sclerosis, ALS, etc., face challenges when learning to program in block-based programming environments, because these environments are highly dependent on the physical manipulation of a mouse or keyboard to drag and drop elements on the screen. In my dissertation, I make the block-based programming environment Blockly, accessible to students with upper body motor impairment by adding speech as an alternative form of input. This voice-enabled version of Blockly will reduce the need for the use of a mouse or keyboard, making it more accessible to students with upper body motor impairments. The voice-enabled Blockly system consists of the original Blockly application, a speech recognition API, predefined voice commands, and a custom function. Three user studies have been conducted, a preliminary study, a usability study, and an A/B test. These studies revealed a lot of information, such as the need for simpler, shorter, and more intuitive commands, the need to change the target audience, the shortcomings of speech recognition systems, etc. The feedback received from each study influenced design decisions at different phases. The findings also gave me insight into the direction I would like to go in the future. This work was started and finished in 2 years.