Hoarseness (known medically as dysphonia) can be a problem for speakers. What can we do? Gary Genard’s Speak for Success! Blog has a useful post on September 20, 2020 titled Public Speaking: 15 easy ways to keep your voice healthy. And there is an article at LinkedIn Pulse on May 12, 2022 titled Hoarse voice before a presentation? 7 powerful treatment secrets from singer, moderator & speaker Danja Bauer.
Wikipedia has an article on Hoarse voice with a long list of references. The twentieth is a long, definitive article by Robert J. Stachler et al in Otolaryngology - Head and Neck Surgery onMarch 2018 (pages S1 to S42) titled Clinical Practice Guideline: Hoarseness (Dysphonia) (Update). The graphic shown above has one version of their recommendations from the Plain Language Summary. Another version, with what and what not to do, is provided in Table 9 on page 25:
HOW TO PREVENT HOARSENESS
THINGS TO DO:
Adequately hydrate by drinking water daily.
Use of amplification in large noisy spaces can help reduce voice strain.
Rest your voice briefly to prevent voice fatigue, straining, and overuse.
Provide indoor air humidification in dry, arid environments.
THINGS TO AVOID:
Smoking and second-hand smoke from cigarettes, cigars, and pipes that can irritate your airway, throat, nose, and mouth.
Overusing or straining your voice by yelling, shouting, speaking over loud noises, and whispering.
Excessive throat clearing and coughing.
Alcohol and caffeine consumption as it can dry the throat, resulting in mucous thickening.
Use of drying medications.
Similar advice appears in a brief 2021 publication (NIH 14-5160) by the National Institute on Deafness and Other Communication Disorders titled Taking Care of Your Voice. To find more about how your voice works, you can read another article by Zhaoyan Zhang in the Fall 2021 issue of Acoustics Today (Volume 17 number 3, pages 60-68) titled The physical aspects of vocal health. There is yet another article by Steven A. House and Eric L. Fisher in American Family Physician on December 1, 2017 titled Hoarseness in Adults.