Always drill for materials on inhabited worlds. These worlds also will give you the chance to learn about alien technology and refill your oxygen. Previously translated alien keywords will automatically be understood again if encountered later. However, you can manually take a note of what they mean in case you die and lose that ability. By doing so, you will be able to make a more informed decision about a choice that requires alien translation. Note: Starting a new game may randomize the language, so words will be different between playthroughs.