BACKGROUND: Speech in individuals with cleft lip and/or palate (CLP) is a complex myriad of presenting symptoms. It is uniquely associated with the structural difference of velopharyngeal insufficiency (VPI), together with a wide and heterogeneous range of other aetiologies which often co-occur. The nature of the speech sound disorder (SSD) including VPI may also change over the course of an individual's care pathway. Differences in terminology and approaches to analysis are currently used, resulting in confusion internationally. Additionally, current diagnostic labels and classification systems in SSD do not capture the complexity and full nature of speech characteristics in CLP. AIMS: This paper aims to explore the different aetiologies of cleft palate/VPI speech and to relate aetiology with speech characteristic(s). In so doing, it attempts to unravel the different terminology used in the field, describing commonalities and differences, and identifying overlaps with the speech summary patterns used in the United Kingdom and elsewhere. The paper also aims to explore the applicability of current diagnostic labels and classification systems in the non-cleft SSD literature and illustrate certain implications for speech intervention in CLP. METHODS AND PROCEDURES: The different aetiologies were identified from the literature and mapped onto cleft palate/VPI speech characteristics. Different terminology and approaches to analysis are defined and overlaps described. The applicability of current classification systems in SSD is discussed including additional diagnostic labels proposed in the field. OUTCOMES AND RESULTS: Aetiologies of cleft palate/VPI speech identified include developmental (cognitive-linguistic), middle ear disease and fluctuating hearing loss, altered oral structure, abnormal facial growth, VPI-structural (abnormal palate muscle) and VPI-iatrogenic (maxillary advancement surgery). There are four main terminologies used to describe cleft palate/VPI speech: active/passive and compensatory/obligatory, which overlap with the four categories used in the UK speech summary patterns: anterior oral cleft speech characteristics (CSCs), posterior oral CSCs, non-oral CSCs and passive CSCs, although not directly comparable. Current classification systems in non-cleft SSD do not sufficiently capture the full nature and complexity of cleft palate/VPI speech. CONCLUSIONS AND IMPLICATIONS: Our attempt at identifying the heterogeneous range of aetiologies provides clinicians with a better understanding of cleft palate/VPI speech to inform the management pathway and the nature and type of speech intervention required. We hope that the unravelling of the different terminology in relation to the UK speech summary patterns, and those used elsewhere, reduces confusion and provides more clarity for clinicians in the field. Diagnostic labels and classification require international agreement. WHAT THIS PAPER ADDS: What is already known on the subject Speech associated with cleft palate/velopharyngeal insufficiency (VPI) is a complex myriad of speech characteristics with a wide and heterogeneous range of aetiologies. Different terminology and speech summary patterns are used to describe the speech characteristics. The traditional classification of cleft palate/VPI speech is Articulation Disorder, although evidence is building for Phonological Disorder and contrastive approaches in cleft speech intervention. What this paper adds to existing knowledge This paper explores the range of aetiologies of cleft palate/VPI speech (e.g., altered oral structure, abnormal facial growth, abnormal palate muscle and iatrogenic aetiologies) and attempts to relate aetiology with speech characteristic(s). An attempt is made at unravelling the different terminology used in relation to a well-known and validated approach to analysis, used in the United Kingdom and elsewhere. Complexities of current diagnostic labels and classifications in Speech Sound Disorder to describe cleft palate/VPI speech are discussed. What are the potential or actual clinical implications of this work? There needs to be a common language for describing and summarising cleft palate/VPI speech. Speech summary patterns based on narrow phonetic transcription and correct identification of aetiology are essential for the accurate classification of the speech disorder and identification of speech intervention approaches. There is an urgent need for research to identify the most appropriate type of contrastive (phonological) approach in cleft lip and/or palate.