Philippine Linguistics Congress (PLC) allows DR-NTU to archive published version for papers submitted in PLC. However, papers submitted in PLCs held in 2005, 2008 and 2011 are not yet published, so PLC do not hold copyright for unpublished papers. PLC also do not hold the copyrights for the published PLC proceedings from 1998 and earlier.
Accepted version of the unpublished PLC papers can be archived in DR-NTU. The author(s) will hold the copyright of these papers. (verified by Guang Ying via email)