In src/mongo/db/fts/fts_command_mongod.cpp, the "too many text index for" error message is not grammatical:

100  if ( idxMatches.size() > 1 ) {
101      errmsg = str::stream() << "too many text index for: " << ns;
102      return false;
103  }

Version:
$ git rev-parse HEAD
47cacf3a19f9b15fe5f586483b3f3992bb12e7bf