Acute Bronchitis: This is the most likely diagnosis given the symptoms of cough, green phlegm, and loss of voice. Acute bronchitis is a common condition characterized by inflammation of the bronchial tubes, often caused by a viral or bacterial infection, leading to these symptoms.

Pneumonia: This condition, which involves an infection of the lungs, can also present with cough, green phlegm, and potentially loss of voice if there's significant inflammation or if the infection affects the upper respiratory tract. It's a plausible diagnosis, especially if the patient has a fever or difficulty breathing.
Laryngitis: Inflammation of the larynx (voice box) can cause loss of voice and may be accompanied by cough and phlegm production if the cause is infectious. It's less likely to cause green phlegm but should be considered, especially if the loss of voice is a predominant symptom.
Chronic Obstructive Pulmonary Disease (COPD) Exacerbation: If the patient has a history of COPD, an exacerbation could present with worsening cough, increased sputum production (which may be green if infected), and potentially loss of voice due to increased respiratory effort or associated infections.

Pulmonary Embolism: Although less common and not directly causing green phlegm or loss of voice, pulmonary embolism can cause cough and should be considered, especially if there are risk factors (e.g., recent travel, surgery, cancer) or symptoms like chest pain or shortness of breath.
Lung Cancer: In rare cases, lung cancer can present with these symptoms, especially if the tumor obstructs an airway, leading to infection (causing green phlegm) or affects the recurrent laryngeal nerve, leading to loss of voice.
Tuberculosis (TB): TB can cause chronic cough, potentially with green phlegm if there's a secondary infection, and loss of voice if the larynx is involved. It's less common in some regions but critical to diagnose due to its infectious nature and the need for specific treatment.

Cystic Fibrosis: This genetic disorder leads to persistent lung infections and could present with chronic cough and green phlegm. Loss of voice might be less common but could occur with significant respiratory distress or secondary infections.
Bronchiectasis: A condition characterized by damaged, widened airways, potentially leading to chronic cough, green phlegm, and, less commonly, loss of voice if there's significant respiratory involvement or secondary infection.
Relapsing Polychondritis: A rare autoimmune disorder that can cause inflammation of the cartilaginous structures, including those in the respiratory tract, potentially leading to cough, phlegm production, and voice changes due to laryngeal involvement.