Meaning: Each of the twelve named periods into which a year is divided.
Learn more about numeral incorporation that you can use for a number of months as demonstrated below.
Meaning: Two months.
It's a phrase of two signed words TWO + MONTH, whereas below is a single sign TWO-MONTH because the number is incorporated with the sign MONTH.
It's a single sign, incorporating the number with the MONTH (numeral incorporation).
Another tutorial shows you how to tell a month from January to December in calendar.
First 100 words.
As you feel more comfortable with the first few hundreds of ASL signs, progress further with your vocabulary and learn signing more.