Environment: Sphinx 0.9, FreeBSD
Sphinx port has libstemmer options commented out in Makefile. With automatic upgrades, it loses stemming for anything except for default EN and RU.
Procedure of rebuilding the port with libstemmer
# (become root)
Create file Makefile.local with this line:
tar zxvf ../../libstemmer_c.tgz
Do not forget to rebuild index if you did not use libstemmer before