Now we have a nice table with all translated pages numbers:
One can easily see that English is the number two source language. Number one is Spanish, and the explanation for this is the very high activity of translation from Spanish to Catalan.
But for almost all other languages English is the prime source. (Some other special cases: For Kyrgyz it's Russian, for Norwegian it's Bokmal, for Minangkabau it's Indonesian. For Portuguese, English and Spanish are similar: 18 and 20.)
The numbers for Spanish are especially showing: Even though the quality of the machine translation from English to Spanish is lower than the quality of the machine translation from Catalan or Portuguese, 72 articles are translated from English, 16 from Catalan and 6 from Portuguese. The likely interpretation is that the English Wikipedia has content that is more attractive to translators even if MT is not great.
Currently the English language appears in the "From" selector in the CX dashboard in wikis where Content Translation is enabled, but it is not available on English Wikipedia itself, not even as a beta feature. This means that improvements to bring more people into the translation interface (new entry points) are not made available in the most used source language. We think that enabling CX as a beta feature in the English Wikipedia will help users to easily start translating, thus resulting in more translations to all languages.
If we deploy CX to the English Wikipedia, we can also enable English as a target language for CX. That will allow users (only those enabling the beta feature) to publish translations in English Wikipedia. This decision is independent from the former one, although there's no reason not to do it. As with other wikis, we can simply track the deletions of the articles and listen to the community's feedback, and disable it as a target, or change the target namespace to User or Draft if needed. As of March 27, the number of articles deleted from the mainspace is negligible: only two articles were deleted as vandalism or bad translations out of 623 that were translated and kept (7 others were deleted as testing edits).
Finally, some community discussions were already held in the English Wikipedia about this and the response was positive:
The proposal is:
* To enable the ContentTranslation extension as a beta feature in the English Wikipedia.
* Publishing will be the same as in other languages - to the main space. We shall track deletions and user feedback and change this configuration accordingly if needed.
* The source languages, initially, will be the same languages in which CX is already enabled. (Theoretically we could enable any language, but for the sake of simplicity let's just add them as we enable CX in the respective wikis.)