The interpretation of numerals has been traditionally debated across disciplines including, but not limited to, Linguistics, Developmental Psychology, and Philosophy. A big portion of the debate concentrates on the ontology of numerals, i.e., their basic meaning, and the mechanisms by which (non) exact interpretations (e.g., at least) are derived. While I adopt the Scopal Analysis of numerals where their semantic denotation is exact (Kennedy 2013, 2015), one question that remains rather underexplored is the relationship between our Number System and our Language System. In this dissertation, I propose the Lexical Refraction Hypothesis (LRH) in which numerals and other number-related morphemes, draw their denotative meaning from the Number faculty, with our language faculty mediating this process. Evidence from pre-verbal infants shows that humans, as well as non-human animals, possess a non-linguistic Approximate Number System (ANS) that allows us to make non-exact quantity judgments. What makes human vs non-human animals different? I propose that the natural lexicon is the vehicle by which the ANS representations are expressed as exact numerosities. Results from Experiment 1 confirm a relationship between Number and Language via Path Analysis. I then conducted a Mediation Analysis to determine if the lexical measure mediates between the two numerical systems. Results show that 75.5% was mediated by lexicon. The results are consistent with my hypothesis that the lexicon mediates between ANS and natural language quantifiers. In addition, I test whether children's estimation on the Number Line Task predict their interpretation of numerals. Unlike previous research (Musolino 2004), numerical cognition is a central variable in my dissertation not only to prove a connection between Number and Language, but also to determine whether our Number System has an impact in linguistic interpretations. As expected, children's numerical cognition significantly predicted their acceptance of numeral interpretations. While I adopt the Scopal Analysis of numerals, I also include Executive Function measures to rule out an implicature analysis of numerals. Based on previous literature, executive functions, such as inhibition, affect participants' interpretations in calculating scalar implicatures. If numerals have a basic exact semantic meaning, then we should not see a significant effect of executive function measures on numeral interpretations. In contrast to earlier work on conversational implicatures, results shows that neither lexicon nor the Executive Function measures were predictive of children's exact interpretations of numerals (p > 0.05). Finally, I test adults' interpretations of numerals in the absence of a modal. The between-subjects Truth Value Judgment Task experimental design consisted of three conditions: an Exact Condition (number of objects matches the target sentence), More Than Condition (number of objects is more than the quantifier in the target sentence), and a Less Than Condition (number of objects is less than the quantifier in the target sentence). Participants were equally divided into the three conditions Results from experiment 3 show that no adults were not willing to relax the exactness restriction in the absence of a modal, consistent with the proposal of Kennedy. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]