I do not know the history of the words affect and effect. I know their use in English, with the words being verbs and nouns respectively, but as a point of curiosity and enthusiasm, I wonder if there is a need to have separate words at all? Is there ever a case where there is a sentence that would be ambiguous if the wrong word was used? For example, consider the following sentences:
I am happy for you too.
I am happy for you two.
(I believe a comma might be needed in the first sentence, but bear with me)
These sentences have different meanings. The first states that the speaker is happy for the listen as well. The second states that the reader is happy for the listener and another individual. It is important, then for English to have different words for these two meanings. Considering affect and effect, is there ever a case where we could have an ambiguous sentence like this? Or could we instead drop either affect or effect and use the remaining word exclusively?
As an aside:
I understand that English is a language birthed from many other languages, and as a result contains many duplicates of words. For example (this is my understanding), cow and beef were at one point essentially the same, but the words are rooted from the languages that were used by those who raised the cattle (Germanic, cow) and those who consumed the meat (French, beef).
Is there ever a case where there is a sentence that would be ambiguous if the wrong word was used?
Both words can be verbs*: “I want to affect/effect change.”
Both words can be nouns*: “The affect/effect is pronounced.”
is [there] a need to have separate words at all?
Probably not. English is full of homonyms and in some cases multiple meanings are grammatical.
I addressed the letter -> Did I put an address on it, or did I give attention to its contents?
The bat flew out of his hands -> A baseball bat, or an animal?
A huge crane fell into the water -> The bird, or the machine?
If we’re able to deal with these ambiguities, we could probably live with a single spelling for affect/effect.
* The verbal form of effect is less common than the nominal, and the nominal form of affect is even less common, but they do, or did, exist.