Background: In head and neck cancer, many tools exist to measure speech impairment, but few evaluate the impact on communication abilities. Some self-administered questionnaires are available to assess general activity limitations including communication. Others are not validated in oncology. These different tools result in scores that does not provide an accurate measure of the communication limitations perceived by the patients. Aim: To develop a holistic score measuring the functional impact of speech disorders on communication in patients treated for oral or oropharyngeal cancer, in two steps: its construction and its validation. Methods & Procedures: Patients treated for oral/oropharyngeal cancer filled six self-questionnaires--two about communicative dynamics (ECVB and DIP), two assessing speech function (PHI and CHI) and two relating to quality of life (EORTC QLQ-C30 and EORTC QLQ-H&N35). A total of 174 items were initially collected. A dimensionality reduction methodology was then applied. Face validity analysis led to eliminate non-relevant items by surveying a panel of nine experts from communication-related disciplines (linguistics, medicine, speech pathology, computer science). Construct validity analysis led to eliminate redundant and insufficiently variable items. Finally, the holistic communication score was elaborated by principal component factor and validated using cross-validation and latent profile analysis. Outcomes & Results: A total of 25 patients filled the questionnaires (median age = 67 years, EIQ = 12; 15 men, 10 women; oral cavity = 14, oropharynx = 10, two locations = 1). After face validity analysis, 44 items were retained ([kappa] > 0.80). Four additional items were excluded because of a very high correlation (r > 0.90) with other items presenting a better dispersion. A total of 40 items were finally included in the factor analysis. A post-analysis score prediction was performed (mean = 100; SD = 10). A total of 24 items are finally retained for the construction of the holistic communication score (HoCoS): 19 items from questionnaires assessing communicative dynamics (13 from the ECVB and six from the DIP), four items from a perceived speech impairment questionnaire (PHI) and one from a quality-of-life questionnaire (EORTC QLQ-H&N35). The reliability is good (five-fold cross-validation: r[subscript s] = 0.91) and the complementary latent profile analysis shows a good validity of the HoCoS, clustering subjects by level of communication performance. Conclusions & Implications: A global score allowing a measure of the impact of the speech disorder on communication was developed. It fills the lack of this type of score in head and neck oncology and allows the better understanding of the functional and psychosocial consequences of the pathology in the patients' follow-up.