This study examines the challenges of reconstructing Proto-Berber within the field of Berber historical linguistics, focusing on ongoing debates concerning lexical origins, phonological change, and language contact. It addresses a methodological issue whereby some analyses rely on the absence of lexical evidence, superficial morphological similarities, or the assumption that the pharyngeal consonant /ḥ/ was absent from Proto-Berber to question the authenticity of certain lexical items, such as Ašlḥi. The study highlights the importance of reassessing the criteria used to determine linguistic origins and distinguishing between synchronic descriptive models, such as the Pan-Berber model, and historical reconstruction based on the comparative method. Using a comparative historical approach, the research combines phonological and morphological analysis, dialectal evidence, and principles of language contact linguistics to investigate changes affecting Berber lexical and phonological structures. The findings show that some claims about lexical and phonological origins may result from confusing the lack of documentation with the absence of a linguistic feature, or from failing to distinguish contact-induced change from direct borrowing. The study argues that lexical and phonological systems are dynamic and subject to historical transformations that may modify word forms without altering their etymological origins. The research contributes to a more cautious methodology for Proto-Berber reconstruction by emphasizing the value of systematic comparative evidence, neglected dialectal data, and a dynamic view of the lexicon shaped by inheritance, internal change, and language contact. It also offers a framework applicable to broader questions in historical linguistics concerning linguistic origins and phonological evolution