Requesting a translation from a foreign-language into English is easy.
If the English article already exists (but a translation would be useful because the article in the foreign language is of higher quality, or includes additional information):
simply place a translation template from the category Category:Expand by language Wikipedia templates on the English article page. For example, to request improvement of the English article on Fuerteventura, based on the equivalent article on Spanish Wikipedia, place {{Expand Spanish|Fuerteventura}} on the English article Fuerteventura.
If the English article does not yet exist:you can:
create a starter article (at least a stub) in English, using the process described at Your first article;
once you have created the article, tag it with a translation template, as mentioned above.
or
add a page request red link in the Requested articles Project section with the proposed title of the article which will contain the translation adding an interwiki link to the foreign-language Wikipedia page(s). Note that fewer people will likely see a request created using this method.
or
ask a translator directly on their talk page, by taking a look at the list of available translators or the category of available translators.
In all cases, articles must meet the relevant notability criteria and other guidelines applicable to articles on the English-language Wikipedia. Each Wikipedia has its own standards, and the acceptance of an article's topic or of any part of its content in one language is no guarantee that it will be accepted in another.
Note that this page is not for requesting translations of copyrighted sources outside Wikipedia. It is also not for articles currently in English Wikipedia that are not in English. For that, please see Wikipedia:Pages needing translation into English.