People strongly prefer to interpret sentences like John said that Mary left yesterday to mean that yesterday modifies left not said. This tendency has generally been attributed to inherent biases in the language comprehension system. An alternative view is pursued, that the comprehension biases emerge from different interpretation frequencies in the language, which themselves emerge from pressures on the language production system to place short phrases before long ones in sentences of this type. A small corpus analysis showed clear differences in productions as a function of phrase length, and two comprehension experiments examined interpretation patterns as a function of phrase length. Results demonstrated a local modification preference only in a long phrase condition, not in a short one. These results support claims that production pressures cause distributional regularities in the language, which are learned and exploited by comprehenders encountering new input.