The scenario above raises many interesting possibilities. There are multiple possibilities for the man's ethnicity as a BHP worker. At the height of the steel mills operation there were work details made of monolingual European men with a single bilingual overseer. Most emigrated from the Mediterranean area - so there is TB and a number of peri-Mediterranean disease to consider like thalassaemia, Mediterranean fever, endemic Kaposi's sarcoma, etc. Then there are the societal correlates of an industrial existence such as exposure to a number of environmental risks including smoking, asbestos, zeolites, dust. Then as a late middle-aged, early old-aged man there are the diseases of retirement - those diseases worked on over the preceding decades with poor eating and general self-abuse - heart disease, lung disease, cancers.
To understand the symptom, you have to understand that there are several possible changes in voice quality, and as an oncologist there are three that I see commonly. But there are others.
Firstly the air being expelled can carry noises generated lower down. In this case the voice is normal as is the cough, there is just a sound overlay, and it is usually high-pitched or 'harsh'.
Secondly the vocal cords can be abnormal. This can take one of two possible causes - failure of the cords to touch together during speech, and cushioning of the touching (from mucosal oedema). The former gives a "hoarse" voice, which is to say a weak voice which lacks the explosive nature of some sounds and is accompanied by a weak non-explosive cough. This has a neural cause. The latter gives a soft voice of reasonably normal form and has a near normal cough.
Thirdly the resonance chamber (pharynx, nasopharynx and nasal cavity) can be abnormal. The most characteristic are the 'blocked nose' speech and the 'hot potato' voice. 'Hot potato' voice is an interesting one. In a child, you think of peritonsillar abscess, and unfortunately if you look for a MP3 to get the sound, you find a band called Likewise which has a 4 minute song called "Peritonsillar Abscess"! In older men, it is characteristic for a supraglottic cancer.
So you need to hear him talk, and look in his mouth/pharynx and then look at the larynx and watch I move when he talks.
Now lets go to the nerve issues. The path of the recurrent laryngeal nerve is interesting because it is non-symmetrical (R v L), and long, so there are many places where it can be affected. It travels as part of the vagus nerve (CN X) - so where is that on the way down and where is it on the way up, and where does it turn?
The turning is different on the right and left. On the left the turning point is the arch of the aorta. This is halfway down the chest and close to mediastinal lymph nodes. On the right the turning point is the brachiocephalic artery. There is little pathologically prone material nearby. So recurrent laryngeal nerve problems are usually on the left side. On looking the left vocal cord rests at the midline and does not tense or move.
What is the effect of two paralysed nerves?