There's no "iinisip" in Tagalog. I think you mispelled it. The root word is "isip" which means "mind/thought" when you want to add the -in suffix, it becomes "isipin (present tense i think)" and its definition becomes "to think." ie, "Isipin mo nga!" (Think about it!). If you want the future tense, add the prefix i- and it becomes "iisipin" ie "Iisipin ko muna" (I'll whink about it). and as to "sinasabi," I can show you the possible conjugations using the -in suffix: sasabihin = to tell example: "Ano ba ang sasabihin ko sa kanya?" (What should I tell him/her?) sabihin = to tell (again. but this time this word is more like . . . imperative) example: "Sabihin mo na kung anong gusto mo." (Tell me what you want.) I really really hope this helps. :D (sorry for the wrong grammar!)

First of all, I guess you wrote the word incorrectly. It is iniisip and not iinisip. The in-affix is used as a direct object marker as opposed to um-affix which is used as a subject marker. More to be used in the passive voice rather than in the active voice. Thus, in-affix verbs are commonly followed by the marker "ng" for object and um-affix verbs are followed by the marker "ang" for subject. Both of your examples are in present tense. Here's how you conjugate the verbs you've listed above. Root word ISIP, in this sense a verb which means think. • Past: Inisip (in prefix + Root word isip) • Present: Iniisip (in prefix + duplicated first syllable + Root word isip) • Future: Iisipin (Duplicated first syllable + Root word isip+ in suffix) • Imperative: Isipin (Root word + in suffix) • Infinitive: Isipin (Root word + in suffix) Root word SABI, a verb which means say. • Past: Sinabi (infix in after initial consonant of the root word sabi) • Present: Sinasabi (duplicated first syllable + infix in between the initial consonant and succeeding vowel + root word) • Future: Sasabihin (Duplicated first syllable + Root word isip + suffix hin) • Imperative: Sabihin (Root word + hin prefix) • Infinitive: Sabihin (Root word + hin prefix) Notice though that the suffix hin is added in certain cases depending on the verb usage. This basically depends on pronunciation. In Filipino, words do change meaning depending on pronunciation. So if the verb to be used has a glottal catch that ends in vowel, just used the "in" suffix. I know this doesn't cover everything about this usage because conjugation alone is such a broad topic in our language. If you need more help or some clarifications, feel free to contact me.

Ok, I think I have it. -in verbs are basically the same as -um verbs, except -in verbs are used as direct object markers.