This study examines the linguistic impact of dialect contact on Qassimi Arabic (QA) speakers residing in Riyadh. Focusing on the morphophonemic feature of the third-person singular feminine suffix (-ah/-ha), the research investigates patterns of convergence and divergence through a variationist sociolinguistic lens. Data from sociolinguistic interviews with 32 QA speakers in Riyadh were analyzed using SPSS. Findings indicate a prevalent use of the non-standard variant [-ah], suggesting a strong preservation of traditional linguistic features among QA speakers despite exposure to other Saudi dialects. This was explained by the concentration of QA speakers in particular neighborhoods creating ethnic enclaves that restrict exposure to other Saudi dialects and thus preserving pre-migration speech patterns. The suffix’s morphophonemic function and lack of social or symbolic meaning also had a role in its preservation.