The present invention provides a non-twisted yarn and an extrusion coated reinforcement yarn and their methods of manufacture, by coating non-twisted glass filaments with a sizing composition and combining the filaments together side-by-side to provide a sized non-twisted yarn, wherein the sizing composition becomes ductile in a molten thermoplastic resin to free the non-twisted glass filaments for radially inward movement while in the molten thermoplastic resin to provide the non-twisted yarn with an essentially round cross-section suitable for extrusion coating with the molten thermoplastic resin.