Reminder to myself: It is worth the effort of installing Drupal straight away in the language that the admin users later will be using. Even if you can change the default language straight away after installation it still leads to a weird mix of some modules taking the default language from what was default during installation and some of what currently is default.
And while it might be cumbersome for me to come up with the right words in other languages in menus, terms etc - it is those admins and editors who will spend much more time using the site than me in future.

I'm working on the configuration of a bi-lingual site so that the partners in Tanzania can add Kiswahili translations. Since I was asked to explain afterwards what I've done, I'll just blog here while I go along.
The site is bi-lingual (English and Kiswahili), and content that is not translated is not supposed to be shown on the other language version. There are polls on the site which don't need to be aggregated. But all the interface and text like the footer do need to be bi-lingual.

On there is a group for Swahili (which according to Wikipedia is the same as Kiswahili...) but no contributions have been made at all there. If any translations done for this site would be submitted there, then that would be an added bonus.
Among the modules installed is are also modules for the 'ICanLocalize' service. However, according to their website, ICanLocalize does not offer Swahili translations ( so I turned these modules off. Two roles have been set up for ICanLocalize translators or managers, which are redundant now. Instead I've added another role "translator" with the appropriate rights. I'll configure Localisation Client instead. For now I leave that one out while I configure all other content types, dis-allowing "language neutral" to enforce the appropriate display of future content.
Since the English and Swahili version of the site are only supposed to show content in the specific language, the language should be set to "Only current language" with a language switcher, and with links to the translations hidden (admin/settings/language/i18n). Navigation from one language to other will therefore only be possible through the language switcher block.