The sound system of any language consists of consonants and vowels. These segments combine to form larger prosodic units, such as syllables. Universally, vowels typically occupy the peak or nucleus of a syllable, while consonants surround this nucleus. Vowels, being the most sonorous segments, are produced without obstruction as air flows freely from the oral or nasal cavities. Vowels can be simple (monophthongs) or compound (diphthongs). In this chapter, we focus on diphthongal vowels in Ardalāni Kurdish, a subvariety of Central Kurdish. The sections are organized as follows: Section “Introduction” introduces the Kurdish language and its three main dialects, narrowing down to Ardalāni Kurdish. The phoneme inventory of the variety under study will be covered separately by consonants and vowels in sections “Consonant Inventory” and “Vowel Inventory.” Section “Review of Literature” examines earlier research on diphthongs, glides, and the distinction between glides and vowels from both phonetic and phonological perspectives. Section “Methodology” outlines the research methodology, including participants, tools, and data elicitation. Section “Kurdish Diphthongs: VV or VG” discusses the phonological and phonetic nature of diphthongs, exploring whether they are true diphthongs or combinations of vowels followed by glides. Section “Phonological Nature of Diphthongs” discusses the phonological arguments both supporting and opposing the existence of diphthongs in Ardalāni Kurdish. Section “Phonetic Nature of Diphthongs” presents an acoustic analysis of the data. Section “Conclusion” provides concluding remarks and findings to resolve these debates.