ZAB Controller voiced concern regarding the continuing confusion regarding the 'resume normal speed' phraseology as it relates to RNAV arrival procedures.

Narrative

A B737 was on the GEELA5 (second day of the new procedure). The speed/altitude at SCOLE is the same as the GEELA4; FL250 at 280 KTS. The B737 was at the end of a stream of around 10 aircraft. The aircraft in front of the B737 was assigned 270 KTS by ZLA60. The B737 did not have a speed in the data block meaning that they should comply with the 280 KTS published speed. When the B737 came over; they were much faster than the aircraft in front of them. I asked them their indicated; they said 305 KTS. I asked them if they had been assigned something by ZLA; they said they were issued 'resume normal speed.' I told them normal speed on an RNAV procedure means comply with the speeds on the procedure. I slowed them; gave them descend via; but due to an increasing compression problem; ended up having to turn them out to keep five miles. I don't really blame the pilot for this problem because a phrase should not have dual meanings in the system. In most cases; other than RNAV procedures; resume normal speed means disregard the previously assigned ATC speed and do whatever you want. In the case of RNAV procedures; it means do whatever you want up until the time you need to comply with the published speeds. This might be an endemic interpretation to ATC; but supposedly pilots have been given the same interpretive guidance. Obviously; due to continuing discontinuities with understanding between pilots and controllers; the education effort is not paying dividends. Like my last report; I believe the work group needs to be convened; collaboratively; to fix the education; procedural design problems; and FMS issues within the system. We all understand RNAV and RNP are the future of ATC; but latent error potential has to be fixed prior to the procedures proving themselves to be efficacious.