“MAG-ISIP” means “to think”. Like “umisip”, it is the infinitive/imperative verb form used in subject-focused sentences. “Mag-isip” though is used much more often than “umisip”. The meaning of “MAISIP” is akin to “to think”, but would translate more to “to come to mind”. Examples: A: “MAG-ISIP/Umisip ka ng libro na sinulat ni Charles Dickens” = Think of a book written by Charles Dickens. B: “Sa ngayon, wala akong MAISIP, pero baka mamaya may MAIISIP din ako.” = Right now, nothing comes to mind/I can’t think of any, but maybe later something will come to mind/I will be able to think of something”. “MAG-ISIP ka muna bago ka kumilos. Hindi tama na ginagawa mo kahit ano lang ang MAISIP mo.” = Think first before you act. It’s not right that you do just whatever comes to mind/you can think of. “Kahapon pa NAG-IISIP si Mary kung ano ang ireregalo niya kay John, pero hanggang ngayon wala pa rin siyang NAIISIP (or MAISIP)” = Since yesterday, Mary has been thinking of what she will give John as a gift, but up to now nothing is coming to mind/she can’t think of anything. “NAISIP ni Mary na huwag na lang pumunta sa party ni John para hindi na siya MAG-ISIP pa ng regalo” = It occurred to Mary to just not go/Mary thought of just not going instead to John’s party so that she does not have to think of a gift anymore.

Dear Nathan, If you translate mag-isip and maisip in English, both word will mean think or to think. However the usage of maisip (ma+verb) indicates the capability to do something. For example: Hindi ko maisip ang sagot sa tanong mo. (I can't think of the answer to your question.) Huwag mong bigyan ng maraming pagkain ang bata, baka hindi niya makain. (Do not give the child too much food, he may not be able to eat it.) In your sentence: "Gayunman, maaaring mahirap mag-isip nang malinaw bago magsalita, lalo na kung tayo’y nagagalit, natatakot, o nasasaktan." Mag-isip means to think as action. Mag+verb is in infinitive or imperative form. For example: Infinitive: Mahirap mag-isip ng sagot sa tanong mo. (It's hard to think of an answer to your question.) Imperative: Mag-isip ka ng mabuti para sa iyong kinabukasan. (Think well for your future.) Sana nakatulong sa iyo ang sagot ko. Mahirap mag-isip ng sagot, minsan wala akong maisip. :)

maisip is also to hopefully be able to remember something that might have otherwise been farthest from the mind....to be able to think of something when the thinker has other things which he deems more important to think about.... It is a really humble wish, saying, I have no right to impose this on you, but I hope that you also, in due time, ( no one knows when that would be), would finally come to realize it, or remember it.

mag-isip is deliberate, intentional, effortful maisip is wishfully to be able to see or realize something, by some providential means... that's it, mag-isip is to think and maisip is to come to realize.

mag isip is try to think about it. or start thinking about it. or go think about it. maisip is for someone to hopefully come to think about it in a future time.