Asthma exacerbation: Given the patient's history of asthma, sudden onset of sob and wheezing, and ability to talk in complete sentences, an asthma exacerbation is the most likely diagnosis. The presence of inspiratory stridor, although less common in asthma, can occur, especially if there is significant airway obstruction.

Chronic obstructive pulmonary disease (COPD) exacerbation: Although less likely given the patient's age, a COPD exacerbation could present similarly, especially if the patient has a history of smoking or other risk factors.
Vocal cord dysfunction: This condition can mimic asthma and present with inspiratory stridor and wheezing, often triggered by stress or anxiety.
Foreign body aspiration: Although the patient is able to talk, a partial obstruction could still allow for some speech, and the sudden onset of symptoms could suggest an acute event like aspiration.

Epiglottitis: Although the patient is afebrile and has no swelling, epiglottitis can present atypically, and the presence of inspiratory stridor is a red flag. This condition requires prompt recognition and treatment to prevent airway obstruction.
Anaphylaxis: The sudden onset of symptoms, including wheezing and stridor, could suggest anaphylaxis, especially if there is a history of allergies. The absence of fever and swelling does not rule out this diagnosis.
Angioedema: Similar to anaphylaxis, angioedema could cause airway obstruction and present with stridor, although typically there would be swelling of the face, lips, or tongue.

Tracheal stenosis or tumor: These conditions could cause inspiratory stridor and wheezing but are less likely given the acute presentation and lack of other symptoms such as hemoptysis or weight loss.
Paradoxical vocal cord motion: A rare condition where the vocal cords move inward during inhalation, causing stridor, which could be considered if other diagnoses are ruled out.