내일봐 = see [you, or: each other] tomorrow 내일보자 = let's see tomorrow 봐 and 보자 are forms of the same verb, which vocabulary form is 보다 (to see). you can check the conjugation of 보다 here - http://www.verbix.com/languages/korean.php?verb=%EB%B3%B4%EB%8B%A4&Submit=Go verb stem 보 + present tense suffix 아 = 보아 --> 봐 (but you will probably never see the "full" form 보아, the standard is 봐) 봐 = see (declarative present informal low) verb stem 보 + "let's" suffix 자 = 보자 보자 = let's see (propositive present formal low) also, under the following link rules of conjugation for present tense are described. http://hwcdn.libsyn.com/p/b/3/8/b38b3891a4e7bcd8/ttmik-l1l16.pdf?c_id=1552194&expiration=1407434474&hwt=43c8026ccf11fc86269ca26e820476ff the teachers deal here with the informal polite style (each verb form ends with -요); to get the style which is used in your question (informal non-polite, or intimate, or low) you'll just have to drop -요. rules for verb stem and suffixes are the same. hope it wasn't too confusing ;)

봐 and 보자 are the same verb, 보다. If you look at http://dongsa.net/?search=보다 you will see many of the forms. You can see that 봐 is 'propositive present informal low', and 보자 is 'propositive present formal low'... both mean "let's see". There are already some good answers on italki about 함께 and 같이. Just google for "함께 and 같이"