Comment 9 for bug 129081

Of course you are free to have a /debian in your tree. As long as its excluded once you make dist (or whatever you use to make your tarball) thats fine.
I'm personally not very happy to ship an extra copy of libspeex just for the purpose of your package.
I discussed with some developers and they are of the opinion that we shouldn't use the bundled one if at all possible.

1) We want to minimise the number of live copies of libraries in the archive.
2) Since our resources for Universe are limited, remaining synced with Debian's source versions poses less of a risk, generally, than bundling our own.
3) Since speex is a main source package (with several rdepends), our opinion is that we should not bundle further updates of our (Ubuntu) own in this dev cycle.
4) We think it would be very unwise to bundle a snapshot in the 8.04 dev cycle (its LTS for us). We should act as if binary packages will only be installed once and not updated via any mechanism. Will the program using the libspeex snapshot be stable and useful for 18 months?

In the meantime perhaps it makes sense for you to investigate if and when the "stable" release will be available, since its in beta2 already.