aspell doesn't warn when given an unknown language string

[Robin Sheat]

If I run, say:

$ aspell -l en_NZ --mode=tex check file.tex

or

$ aspell -l en_BLAH --mode=tex check file.tex

aspell will continue on and do its spell checking in en_US, which is very incorrect behaviour. It should throw an error rather than proceed on doing the wrong thing.

If I use en_GB it'll use correct spellings for that language.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: aspell 0.60.7~20110707-1.3
ProcVersionSignature: Ubuntu 3.19.0-21.21-generic 3.19.8
Uname: Linux 3.19.0-21-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Jun 27 15:54:06 2015
InstallationDate: Installed on 2011-04-26 (1522 days ago)
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
SourcePackage: aspell
UpgradeStatus: Upgraded to vivid on 2015-04-26 (61 days ago)