Why did first gerneration followers of Gautama Buddha chose oral method instead of written verbal method to preserve his teachings?

Whatever Buddha taught, it is for nirvana. Each and every person used to get attain nirvana in different way. Only Buddha know the exact way to achieve nirvana in different person with different background. So Buddha taught in different ways and not every words of Buddha is recorded in Tripitaka. When orally one learn from the enlightened, it goes deep down to heart even can get nirvana before ending of verse. Orally received teaching vibrate your entire heart and can tame even the animal to get to higher abode. If you have chance to listen to the Dhamma of some great venerable monk, you will know what it means.

The really basic answer is that the subcontinent had a longstanding oral tradition stretching back to at least 1200BC, which can be determined from linguistic analysis of the Rig Veda.. Just common practice until about 300-200BC probably!

I have a great hunch as to why:

• You don't need writing for survival, you need food, water, and shelter for survival
• Reading/Writing consumes many resources (The Buddha was against destroying plant life)
• Evidence shows that reading causes headaches, nausea, and myopia indicating that our brain was never specified for reading and writing
• The achievement of arahantship does not rely on reading/writing but instead on the ending of mental fermentations
• Illiterate people can learn and accomplish the same things as literate people learning orally or with images or video
• Oral recitations may benefit self-discipline, memory, and concentration
• Learning things orally consumes very few resources and doesn't require that someone know how to read/write
• The Buddha predicted that the pure dhamma would disappear within 500 years...no amount of writing things down would've changed that

For me personally I notice that I can remember most things much better if I orally recite it a few times rather than if I try to visually memorize it so oral recitations are really useful for me. I had memorized many things this way like my credit card numbers, driver's license number, etc...

I also think that humans in general may learn many things better without writing (learning orally, using images, video, or through experience). So it may be a good direction for society to abandon writing or lessen the use of writing in the future.

Just imagine if you achieved arahantship would writing things down really help anyone out in achieving arahantship (the ending of mental fermentations)? It's experience vs. reading. Would reading archery books (with no images, video, etc...) cause someone to become an excellent archer or would the actual experience of practicing archery cause someone to become an excellent archer?

In many conditions reading something won't matter or help much at all whereas experience really matters (for everything in general).

I notice that even if I give exact precise instructions a lot of people still won't get it or achieve anything.

So it makes sense to me that The Buddha didn't care about writing things down.

In the future since a food/water crisis seems likely writing may be abandoned or only reserved for some few. We're cutting down trees and using lots of resources on literacy and reading/writing instead of on food, water, and shelter.

The difference between literate vs. illiterate is oral vs. written. That's really it.

Remember in the Dhammapada The Buddha says:

"Much though he recites the sacred texts, but acts not accordingly, that heedless man is like a cowherd who only counts the cows of others — he does not partake of the blessings of the holy life.

Little though he recites the sacred texts, but puts the Teaching into practice, forsaking lust, hatred, and delusion, with true wisdom and emancipated mind, clinging to nothing of this or any other world — he indeed partakes of the blessings of a holy life." (Dhammapada, 1.19-20)

It seems like The Buddha wanted to encourage people to act on the teachings that lead towards arahantship rather than encourage people to focus on superficial things.

I don't know but maybe writing hadn't been invented there yet (or not introduced from elsewhere), or at least it wasn't common.

Wikipedia says,

First appearance of writing in the Indian Subcontinent

The first introduction of writing to the Indian Subcontinent apart from the Bronze Age Indus script, which is undeciphered and may not be an actual script, is mostly identified as the Edicts of Ashoka from c. 250 BCE.

The same is true of Hindu texts, i.e. the earliest records of writing dates from a couple of hundred years after the Buddha,

Sanskrit -- Origin_and_development

The earliest attested Sanskrit texts are religious texts of the Rigveda, from the mid-to-late second millennium BCE. No written records from such an early period survive, if they ever existed.

The article on Brahmi script says,

Brahmi (brāhmī) is the modern name given to one of the oldest writing systems used in South and Central Asia during the final centuries BCE and the early centuries CE. ... The origin of the script is still much debated, with most scholars concurring that Brahmi was derived from or at least influenced by one or more contemporary Semitic scripts, while others favoring the idea of an indigenous origin or connected to the much older and as-yet undeciphered Indus script.

So, who knows, perhaps that kind of writing was introduced via the Alexandrian empire.