Recurrent Laryngitis or Chronic Laryngitis: This condition is characterized by inflammation of the larynx, which can lead to hoarseness, cough, and difficulty speaking. The symptoms worsen with vocal use, and improvement with hydration supports this diagnosis, as dryness can exacerbate laryngeal irritation.

Gastroesophageal Reflux Disease (GERD): GERD can cause stomach acid to flow up into the throat, leading to irritation, hoarseness, and cough. The symptoms of throat itchiness and scratchiness could be related to acid reflux.
Vocal Cord Lesions (e.g., Polyps, Nodules): These growths on the vocal cords can cause hoarseness, difficulty speaking, and cough due to the mechanical disruption of normal vocal cord function.
Allergic Rhinitis or Postnasal Drip: Chronic postnasal drip can irritate the throat, leading to cough and hoarseness. The symptoms started after a respiratory illness, which could have triggered or exacerbated allergies.

Laryngeal Cancer: Although less likely, laryngeal cancer must be considered, especially in patients with a history of smoking or significant voice changes. Hoarseness lasting more than 2 weeks is a red flag symptom.
Tuberculosis (TB): TB can affect the larynx, causing hoarseness and cough. Given the duration of symptoms and the initial onset after a respiratory illness, TB should be considered, especially if the patient has been exposed or has risk factors.
Sarcoidosis: This autoimmune disease can affect the lungs and the larynx, leading to symptoms like hoarseness and cough. It's less common but critical to diagnose due to its systemic implications.

Relapsing Polychondritis: A rare autoimmune disorder that can cause inflammation of the cartilages of the body, including those in the larynx and trachea, leading to hoarseness and respiratory symptoms.
Amyloidosis: The deposition of amyloid proteins in the larynx can cause hoarseness and other symptoms. This condition is rare and usually associated with systemic disease.
Foreign Body or Trauma: Although unlikely given the duration and nature of the symptoms, a foreign body or trauma to the larynx could cause chronic symptoms if not properly diagnosed and treated.