Irregular words consistently present challenges for novice learners, and this difficulty tends to escalate, particularly among children with dyslexia. One of the linguistic elements contributing to irregularity in word form in Farsi is "tashdid", which involves the gemination of a letter. As tashdid does not usually appear in the script, distinguishing geminate from non-geminate words poses difficulty for Farsi readers. To explore what factors impact reading geminate words in children with dyslexia (N=30) and without dyslexia (N=30), we focused on two key variables: frequency and neighbourhood density (size), both categorized into high and low levels. We conducted a lexical decision task to examine the impact of frequency and neighbourhood density on the recognition of geminate words, while controlling for word length. We analyzed both accuracy and response time, employing mixed-effect regression modeling methods. The findings indicated that within the typical group, an increase in both neighborhood density and frequency corresponded to heightened accuracy and decreased response time. The dyslexic group exhibited a similar pattern, but the magnitude or strength of the pattern exhibited a statistically significant decrease. Moreover, when considering the interaction between these variables, our results revealed an intriguing insight: Children with dyslexia exhibited less sensitivity to frequency and neighborhood density. In children with dyslexia, higher accuracy was observed when the neighborhood size was high and the frequency was low, contrary to the expected impact of high-frequency effect. This observation sheds light on an intriguing aspect of word recognition, especially among individuals with dyslexia, challenging the conventional expectations regarding the influence of frequency and neighborhood effects.