Thanhs for writing to H.C.M.
I have gone through your query regarding throat pain of your wife specially on talking too much or speaking loudly while her other activities related to throat are normal.
Keeping this in view she may be having laryngitis
(involving cricoarytenoid joints).
This may be treated by-
(a) Anti inflammatory & analgesic
(b) Steam inhalation.
I hope this will help her , but if even after this she had pain than thorough examination by ENT specialist
will be necessary for further treatment.