To get the month names you can use the following function module.
Please find the program below.
data: d_return like sy-subrc,
itab_T247 like T247 occurs 0 with header line.
CALL FUNCTION 'MONTH_NAMES_GET'
LANGUAGE = SY-LANGU
RETURN_CODE = d_return
MONTH_NAMES = itab_T247
MONTH_NAMES_NOT_FOUND = 1
OTHERS = 2
IF SY-SUBRC <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
* WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
Loop at itab_t247.
Please not that you can use the table T247 to get all the Months names. The above function module is an RFC and can be called from another SAP or NON SAP system.