the use of gè

NIhao, Does gè mean anything on its own? why is it in yî gè yuè to say one month?

It means "only." So in essence, the phrase is "only one month."

Ge4 / (Ge5) is the universal measure word, that you can use when there isn't another measure word to use, or you don't remember the right one. One *measure word* month. Yi4 Bei1 Ju2zi5shui3 A *Measure word for glass/cup* orange juice. EDIT!!!!!!! - After taking a Mandarin course in college I have learned that saying orange juice like how I did so above will only get you blank stares. use cheng2zhi1 or ju2zizhi1 instead.