[CrimsonNataku]

Pink_Knight: Watashi wa Boston no Massachusetts kara kimashita. John-san wa? (If the question is already understood, you don't have to complete the sentence when speaking in conversation).

Kira_2009: I've studied Japanese for 4 years. Part of that time I studied on my own, but I also took an intensive Japanese language immersion summer camp for two years. I attended only one Japanese class for a semester, and I am currently studying Japanese on my own and with a tutor because I keep placing out of the classes at the local community colleges. I also tutor a few students in Japanese, which also helps me remember/practice/learn.

rosaline144: Kochira koso yoroshiku, Rosaline-san. (Kochira koso yoroshiku basically means "Pleased to meet you too." It is the customary response to "Hajimemashite, yoroshiku onegai shimasu.") Rosaline-san no nihongo wa totemo ii desu ne. Dono kurai nihongo wo benkyou shimashita ka.
And to answer your question, the suffix to imply that a noun is plural is indeed "tachi," so saying tomodachi-tachi would mean friends. However, usually the plural is understood based on context, so it is often unneccessary.