Prior studies of noun–noun compound word processing have provided insight into the human capacity for conceptual combination (Gagné and Shoben Journal of Experimental Psychology: Learning, Memory, and Cognition, 23(1), 71 1997; Spalding, Gagné, Mullaly & Ji Linguistische Berichte Sonderheft, 17, 283–315 2010). These studies conclude that relational interpretations of compound words are proposed and appraised by the language system during online word recognition. However, little is known about how the capacity for creating new meanings from existing conceptual units develops within an individual mind. Though current theories imply that individual relational knowledge about the combinability of concepts develops as language experience accumulates, this hypothesis has not been previously tested experimentally. Here, we addressed this hypothesis in a task that assesses individual relational knowledge of English compound words. We report that greater experience with printed language shapes relational knowledge of compound words in two ways. Firstly, individuals with more experience with printed language were able to select a greater number of possible relational meanings for individual compound words. Secondly, individuals with greater experience with printed language were also more precise about which relational meaning was the most semantically plausible out of all possible meanings. Our results confirm that language experience affects an individual’s ability to use relational knowledge in order to combine conceptual units. Our findings offer further support for the Lexical Quality Hypothesis (Perfetti, 2007), which states that lexical representations of words become simultaneously more flexible and precise as a result of repeated exposure to their orthographic forms in language usage.