When can I use "initiate"? What's the difference with "start"?
"Initiate" and "start" are synonyms for each other, both with similar meanings of beginning or causing something. Generally, "initiate" is a bit more formal in feeling and is related to the action of causing a process or action to begin. This video is concerned with scientific tips for sleeping better, and as he describes "sleep" as a process, the speaker has likely chosen to use "initiate" instead of "start." Regardless, "start" can also be used in this context. Ex: You may find it helpful to lower your room temperature in order to start sleeping and then to stay asleep. Ex: Students have just started their fall semester.