Binary package hint: debian-installer
Using Ubuntu Alternate i386 (20080930.4) Intrepid-Beta Iso on an old machine (233 Mhz, 160 Mb RAM) it takes a lot of time to install. I don't have any problems with that, but as I inspected on the terminal (via alt+f4) what was happening during the installation process I saw, that it was generating every single en_XX@UTF-8 locale.
Actually it shouldn't, because I only ticked (in expert mode btw) en_US@UTF-8, de_DE@UTF-8 and fi_FI@UTF-8 and it was taking an awful lot of time generating all these en_DK@UTF-8, en_NZ@UTF-8 etc. locales.
I was using the expert mode, nolapi noapic, pci=irqmask=0x0e98, keyboard-layout 105 (Intel) key - germany - nodeadkeys and a Finnish location and time zone. The standard locale was set to be de_DE@UTF-8, the terminal was also set to UTF-8. I had only the CD and no network access, thus denying network access when prompted.
I would have expected it to install and generate en_US@UTF-8 and, if on the CD, also fi_FI@UTF-8 and de_DE@UTF-8
Instead it installed all flavors of en_XX@UTF-8 and silently skipped the other languages. Later on (after installing, in GNOME via an information box in the upper right-hand corner) I was warned, that the locales were not installed completely and I could fix it now if I had internet access.
I don't know, which flavor of en_XX@UTF-8 it actually used, because I don't know, how much of the specific locales is translated, but at least some man-pages seamed to be en_US@UTF-8 (that is, they used american english)
Language packs all generate all the UTF-8 locales for their language when installed; the behaviour is AFAIK intentional but at any rate is controlled by the belocs-locales-bin package.