Hi!, I am a 1st year PhD student, in linguistics. I am a little more than a month into my PhD. I have my next supervisory meeting in the middle of this month. I have been advised to write a summary of the literature I have read so far and how they are applicable to my area of research. Could anyone give an idea of how long these should be? Please help.

You should ask your supervisor for the desired scope of your report including length. It will differ from supervisor to supervisor.