I read that the buddha had not wrote anything. He was used to speak Magadha language. Then sanskrit and pali language appeared when his disciples wrote down his life & experiences. I have already asked a question on language. This time i have a question that states 'why buddha didn't wrote anything ?'.
(I'll assume the actual question is in the body, not in the title).
Naturally, no one can answer why someone didn't do something but that specific someone (but if you really wanted to know from the Buddha, you wouldn't be asking this here...). But there are practical reasons that could explain.
Writing is not teaching.
While you are writing, you are not doing anything to anyone. Being in a cave for years writing a lot about something, and then having a flood take all your sheets away can render all those years useless.
Writing is not teaching, and it is visible that the Buddha was primarily interested in helping the actual people he actually met and guiding those interested to become masters of the subject, and then, teachers themselves. As any educator can attest, this is the highest form of education.
There wasn't a broad "reading culture" -- though there were written texts -- at that time and place. Thus, there were not many readers.
To be of great value, writing requires an author who knows how to write and many many readers who were trained to read certain language(s). Moreover, writing is taking a chance that not only someone trained to read that language will meet your texts, but also that he will be interested and he/she will understand as it is -- an unreasonable expectation -- since there is no possibility of real dialogue.
Not only that wasn't common as it is today (nor there were any alphabetization goals that I know of), but understanding (and teaching) the dhamma is hard as it is. It is even harder if, before teaching dhamma, one would have to teach how to read. So, it's just a major distraction and the benefits were hardly guaranteed.
Instead he advised people to memorize discourses (real discourses, to real people with real problems) and always welcomed any questions they had -- the suttas are full of FAQs from disciples to disciples, and disciples to the Buddha. That's a real learning setting. And the discourses were texts, though not in written form. Orality, in any case, is not a poor-man's "literacy".