Balaguer M, et al. - Using acoustic analysis, researchers examined the impacts of oral and oropharyngeal cancer on speech intelligibility via surveying PubMed and Embase databases. In oropharyngeal patients, nasalance is mainly studied. Most of the vowels are studied using formant analysis and vowel space area, the consonants depending on their phonetic characteristics through spectral moments with specific parameters. Machine learning methods can be used to classify speech for T3 or T4 tumors as "intelligible" or "unintelligible." Developing comprehensive models combining various acoustic measures would allow for a better consideration of the speech disorder's functional impact.