This paper aims to examine the articulation of English consonants, vowels and diphthongs by Pashto Speakers in Khyber Pakhtunkhwa, Pakistan, and explores the problems they face in their English articulation due to the influence of mother tongue. A detailed experiment has been carried out to analyze the articulatory properties of /θ/ /ð/ /ɪ: /, /ɪ/ and /еɪ: / sounds spoken by Pashto speakers in Pakistan. The research reveals that Pashtun speakers of English language have a distinct pronunciation pattern of /θ/ and /ð/ sounds. This research provides a scientific justification to establish Pashto English as an independent deviant variety of RP Standard English Language. Based on the findings of the data collected from the recordings of 50 participants, it was concluded that thickness is low and frequencies of formants are considerably low as compared to RP sounds. In this regard, consonant phonemes of /θ/ and /ð/ sounds articulated by Pashto speakers are dissimilar to their Standard English (RP). They are produced as “Dental Plosives” instead of “Dental Fricatives”. The participants face great difficulty in pronouncing these English dental fricatives /ð/, /ɵ/ sounds, and they also face insurmountable problems in the regular plural forms. In relation to vowels and diphthongs in English language, major problems largely appeared in misunderstanding between /ɪ:/, /ɪ/ and /еɪ:/ sound production. The results of this study shall provide assistance to English language teachers and learners in teaching and learning English Language, especially in teaching and learning English pronunciation. It has been ascertained that special consideration should be given to these problematic consonants, vowels and diphthongs in order to avoid misunderstandings/confusion on the part of the listener.