Should we change it to пришёл,
or do we assume that everyone knows (or should know) that?

ummm... we can but we're not required to do it, I'd said. :-) This case is clear enough to not use "ё", I think.

I agree. ^v^

As a beginner in Russian, I'd love to know the difference between the cases where it's clear enough and it's not.

Are the sentences here written in the way native speakers usually write, or are they written in a more or less learner-friendly manner?

> This case is clear enough to not use "ё", I think.

I don't agree at all. What is "ё"?

A small movement of a fingertip for a (russian) man, but a giant help for (the Russian-learning) mankind!

> I'd love to know the difference between the cases where it's clear enough and it's not.

As you know already, we write words not the way we pronounce them, but the "ё" case is special a bit. :-) The cases where the usage of "ё" is mandatory (according to current practice) are the following:
- texts where all words have stress-marks
- children books and junior school textbooks
- textbooks for foreigners studying Russian
- ё is used to prevent variant reading or to show correct pronunciation of a rare word, or to prevent a speech mistake
- proper names
In all other cases the usage of "ё" is optional.
These rules reflect the real state of affairs concerning genuine Russian texts (books, paper articles, etc.). But, of course, there are people who advisedly write "ё" in every word wanting to demonstrate their principled stand. Other people just stick to the rules above or extending them according to their personal preference. This is true for Tatoeba, too. Some 意地悪 Russian learners claims we just have to use "ё" everywhere to ease their learning life but, apparently, this won't help anything due to cruel Russian realities. :-)

We should be thankful that they at least do write vowels — in contrast to the Arabic speakers here on Tatoeba who don’t because that’s also the usual way they write their language in their books and newspapers. One first has to be perfect before one can read it. ☺

@sharptoothed

Thanks for the explanation.

As a native speaker of a language where how to write is extremely important ([#2686962]), I'd like to insist, on one hand, that the sentences in Tatoeba must "look" natural. By that, I mean the sentences written in a way that native adults would write when they write to native adults. I don't think we should collect sentences written in a style of children's books and textbooks. So we don't have sentences like とむは　よく　かわへ　つりに　いきます。 (that's how [#199995] would be written in a children's book).

On the other hand, it would be also nice if Tatoeba could be as friendly to beginners as possible, even though I never support the view that Tatoeba is mainly targeted at beginners, as some argue. I'd be really happy if I could choose to see another text like "Он не пришёл из-за што́рма." under the normal natural-looking text.

What do you think?

> I'd be really happy if I could choose to see another text like "Он не пришёл из-за што́рма." under the normal natural-looking text.

Stress-marks in the Russian could be really helpful for language learners, I guess. But, actually, this won't help much since, you know, stress is not the only thing (and not the most important thing as well) a learner might want to know about the words in the Russian sentence.
Ideally, the more information on a sentence a learner could get, the better, but this would require a bunch of language analysing tools incorporated into the project engine. Meanwhile, the Tatoeba concept, as CK pointed above, is not about providing such tools but rather about collecting high-quality source data for them.
One possible solution could be a plug-in system for Tatoeba so enthusiast members could write add-ons without need of deep understanding Tatoeba internals and source codes, and without bothering Tatoeba developers too much. Of course, this will require implementation of plug-in support in the Tatoeba engine but this is something that should be done only once.