Despite the multifarious studies investigating the acquisition of English as a second language (L2) by Arabic-speaking learners, very few have examined the influence of learners’ dialects on their pronunciation of English consonants. Therefore, this thesis aims to explore the impact of L2 learners’ dialects on their pronunciation of the English affricative and fricative sounds. To achieve this goal, the articulation of the sounds /ʤ /, /θ/, /ð/, and /v/ by 40 female senior undergraduate Saudi learners (20 Hwaiti Bedouins and 20 Hijazi Urbans) at Tabuk University were recorded and then rated by two L1 speakers of English. The main hypotheses were that Hijazi speakers would mispronounce /ʤ/, /θ/, and /ð/ because they are not part of their dialect yet they are part of the Hwaiti Bedouin dialect and that both groups would devoice the phoneme /v/ by pronouncing it as /f/ because /v/ is not in the Arabic sound system. This thesis uses quantitative methods: a demographic information questionnaire, LexTALE English proficiency test, Arabic and English production tasks, along with statistical analyses of the collected data by using RStudio (2021). The errors are classified based on Flege and Bohn’s Speech Learning Model (SLM) (2021). The theoretical framework is an amalgamation of milestone theories, mainly Cross-Linguistic Influence (Bild & Swain, 1989; Tati et al., 2015; Odlin, 1989, 2012; De Angelis and Selinker, 2001), Eckman’s Markedness Differential Hypothesis (1985), and Flege and Bohn’s SLM (2021). Each contributes to the analysis of cross-language interaction, phonological transfer patterns, and L2 phonetic learning. The main finding is that the two groups were affected by their dialect sound systems when producing the selected phonemes. Interestingly, the two heterogenous groups had similarities in the type (albeit not the frequency) of sound substitutions: they both pronounced /ʤ/ as [g] or [ʒ], /θ/ as [s] or [t], and /ð/ as [z]. Moreover, the most challenging phoneme to pronounce by the Hijazi group was /ʤ/ in the middle position of words, whereas for the Hwaiti Bedouin group, it was /θ/, also, in the middle position. Future researchers can expand upon this study to include other dialects. Keywords: Affricate, Dialect, First language, Fricative, Second language.