LaovielTrainers in Silan are special in that they have curated list of stanzas that they present to user. They do not use full list of stanzas like mainland trainers do.
... Whether this is intended, or just an old bug dressed as a "feature", I do not know.Yoh Yawh (the Harvester Trainer on Silan) does not offer any Speed or Rate stanzas for training.
Maybe its time to update that list, but you can visit trainers in mainland and then come back to Silan if you so desire.