hi kaibigan, the pronoun "ka" could also be a short version of "ikaw" = "you", but used differently though. here are some rules in using "ka" and "ikaw": 1. "ka" often comes after a verb: ex. 'kain ka' [eat (you)]; 'pasok ka' (come in); 'natutulog ka ba?' (are you sleeping?) 2. "ka" ofetn comes after the question words: 'saan' (where), 'kailan' (when), 'sino' (who), 'bakit' (why) and 'paano' (how). 'ano' (what) can also be considered as an expression: "ano KA ba?!" 3. "ikaw" is, most of the time, used at the beginning of a sentence. let's try to contrast the two pronouns: "kumain KA na ba?" (have you eaten?) "IKAW ba ay kumain na?" (have you eaten?) this is wrong: "kumain IKAW na ba?" / "KA ba ay kumain na?" "mo" is also a 2nd person pronoun (sometimes in possesive case) = "you", but it differs to "ka" with respect to the form of the verb being used: let's say, "KAIN" (eat) 'KumAIN ka." (you eat / eat some) - suggesting to take a food to solve starvation. (SUGGESTION) "KAINin mo." (you eat) - considering the food is already served. COMMAND. "KUHA" (get) "KumUHA ka" (you get some) "KUHAin mo" (you get it) :)

Just read your question and now I am wondering too. OMG! I am a Filipino. I use those words everyday, but I can't explain. I can't even figure out what part of speech in Filipino grammar they belong. I think I should go back to school...