Cleft Lip and Palate Associated With the Phonetic Function: A Systematic Review

TL;DR

This paper reviews how cleft lip and palate affect speech, focusing on specific phonemes and nasality in patients.

Contribution

The study systematically identifies the most affected phonemes and links delayed surgery to increased nasality in CLP patients.

Findings

The phonemes /k/, /p/, and /t/ are most frequently affected in patients with CLP.

Delayed reconstructive surgery is consistently associated with increased nasality severity.

Most CLP patients exhibit mild nasality, but speech impairments are common across languages.

Abstract

Cleft lip and palate (CLP) are congenital malformations of the craniofacial complex that disrupt the structure and function of the stomatognathic system, particularly articulation and phonation. These anatomical abnormalities affect pressure consonants and resonance balance, often resulting in impaired phoneme production and varying degrees of nasality. Understanding how CLP affects speech is essential for guiding rehabilitation and designing targeted early interventions.

This systematic review aimed to identify the most frequently affected speech phonemes and determine the degree of nasality in patients with CLP. A literature search covering the last 10 years (2015-2025) was conducted using PubMed, SciELO, and Scopus. A total of 484 articles were identified, of which 20 met the inclusion criteria. The most affected phonemes across languages were /k/, /p/, and /t/, all voiceless stop consonants. Most patients exhibited mild nasality; however, a consistent association was observed between delayed reconstructive surgery and increased nasality severity.