The Russian Wikipedia page for творог says that its stress could be in either syllable, but that in standard speech, especially in the mainstream media, the stress is only used in the second syllable. Can someone indicate how widely творог is pronounced with stress on the first syllable? Is that generally rare, or is such usage concentrated in certain parts of Russia?
I think the article in the Russian Wikipedia is a little bit speculative. I think he cite sources for творОг (second syllable) because the editors wanted to keep it as is. As a native Russian speaker personally, I don't know which type of stress I prefer. And I don't think one or the other usage is rare. It's obvious that we can't say which usage is most used based only on dictionaries. But I can't find any articles on this topic (stress in творог) and the distribution across Russian spoken countries. In the Russian corpus there are 15 contexts with stress on first syllable (твОрог) and 17 contexts with stress on second syllable (творОг). So I think you can't say which usage is preferred by Russian speakers.
If we talk about cited sources, in this Wikipedia article I only consider this source reliable - Зарва М.В. Словарь ударений русского языка (2001). Two other sources have very questionable reputation:
Штудинер М.А. Словарь образцового русского ударения (2009) Even the name of this dictionary (especially the word образцовый) seems to me very strange. You can find more information in the Wikipedia article on this dictionary.
Окунцова Е.А. Трудности устной речи. Словарь-справочник. Never heard about this dictionary like a foundational text in Russian lexical stress.
Here, in the Russian corpus you have some video examples and transcription with lexical stress for the word творог. In this corpus we have 11 usage contexts and it's твОрог (8) vs творОг (3).
So, here's what I found about stress in творог:
- Толковый словарь живого великорусского языка. В. Даль (1903) <нвг. - новгородское>.
ТворОгъ твОрогъ (нвг.)
- Орфоэпический словарь русского языка. Р. И. Аванесов (1988).
творОг и допустимое твОрог
- Словарь трудностей русского языка. Розенталь Д. Э. (1984).
творОг и разг. твОрог
- Новый орфоэпический словарь русского языка. Иванова Т. Ф. (2005)
творОг и твОрог
My point that творОг is considered more preferable by the purists, but it's not the actual usage of this word. Now we have a clear trend to pronounce it as твОрог (but it's not an actual solid norm, it's just a trend, I think).
EDIT: I found this interesting link in the Wikipedia article Изменение ударения в слове «творог» с XVIII по XXI вв. по материалам словарей русского языка. And actually it's only in Русское словесное ударение. Зарва М. В. (2001) we have one recommendation for творОг. Other cited sources (Окунцова, Штудинер) describe both usage contexts, so in the Russian Wikipedia article is partially wrong information about stress in the word творог. I will edit this article, I think. And I found this explanation about the Зарва dictionary, because this dictionary was conceived for news presenters it's not good for lexical stress reference, because only one example usage was accepted (see gramota portal question # 262504).
So both usages are acceptable; the more contemporary твОрог and the old (and preferred by the purists :-) творОг.
For myself, the stress on the first syllable is much more natural, although I think in the media they usually pronounce it with a stress on the second syllable. Such pronunciation colored as "rural" to me even though it is used more often in the media.
I think in Moscow and Moscow region stressing the first syllable is more widespread.
Here one can see a video the speaker pronounces the word with stress on the first syllable:
Here the speaker stresses the second syllable:
Here the speaker starts with stressing the first syllable but then switches to the second (apparently in attempt to be more "correct"):
I think stressing the first syllable sounds more natural and easy to pronounce, but stressing the second is more grammatical formally (or believed by the people to be more grammatical, as with the word кофе being masculine gender even if more natural to consider it neuter).