Steve Bennett wrote:
Just fwiw, one simple basic example I have dealt with.
[[fr:Carnac]] discusses both the township of Carnac and the famous Carnac stones which are found within the town.
I split [[en:Carnac]] into that article which only discusses the town, and [[en:Carnac stones]] which discusses the megalithic site.
Another example from a different field is [[en:Chloral]] and [[en:Chloral hydrate]]. These are two distinct compounds, and the interwiki linking quite sensibly follows the distinction. However, if you look at the articles, you'll note that there's a lot of redundant information in them: the problem is that the compounds readily convert to each other depending on the presence or absence or water, such that it's difficult to discuss the chemistry of one without also describing the other.
That might make the articles reasonable candidates for merging, and indeed many other Wikipedia have done so. However, there is no agreement on which title the combined article should have. The French article, which is the most detailed one, is at [[fr:Chloral]], despite mainly describing the hydrate. The German, Dutch, Russian and Turkish Wikipedias only have articles on the hydrate. Only the English, Polish and Japanese Wikipedias have both, and on the latter two both are stubs. So was [[en:Chloral]] before I started expanding it -- most of the info is still at the hydrate article.
I suppose the ideal solution would be to either merge or split the articles consistently across languages. But I don't really see that happening soon, and in any case the reasonability of having one or two articles depends a lot on the amount of information present, which varies a lot between different Wikipedias; most, of course, don't have any information at all on either compound.