The present invention concerns a process for making a polyareneazole multifilament yarn comprising: a) extruding a solution comprising polyareneazole polymer and polyphosphoric acid through a plurality of orifices to produce filaments; b) forming a multifilament yarn from said filaments; c) hydrolyzing at least some of the polyphosphoric acid in the yarn by heating the yarn to a temperature aboveabout 120 DEG C for up to about two minutes; d) washing at least some of the hydrolyzed polyphosphoric acid from the yarn; e) drying the washed yarn; f) optionally, heating the yarn above about 300 DEG C, and g) collecting the yarn at a speed of at least about 50 meters per minute.