I will try to give a satisfactory answer to the question. How widely spoken is the Hausa language? I am from the Royal family in Daura where Hausa originated and I have the title of Wamban Daura. Abashe Saidu, former Managing Director at Katsina State Agricultural And Rural Development Authority (1980-2015).
Hausa is the most widely spoken language in Northern Nigeria and there is a large number of Hausa speaking population in the Western Nigeria and Lagos areas. There are even ‘Sarkin Hausawa’ in Ibadan and Lagos.
Hausa is also widely spoken in Niger Republic , Chad and Cameroon. Northern Ghana has a large Hausa speaking population . Hausa speaking people extend west up some areas in Senegal.
I can recall a hilarious incident which happened to me when I attended a meeting in Dakar , Senegal in 1992. I went out in the evening for a stroll in the evening where I saw some people selling a roasted meet we call ‘tsire or suya’ in Hausa. I wanted to communicate to the people to buy the tsire but I can not speak the local language . I started talking to myself in Hausa on how do I communicate with these guys? So I resorted to sign language and to my surprise one of them asked me in perfect Hausa ‘ Alhaji tsiren nawa kakeso?’, meaning – How much tsire do you want to buy? We all laughed.
Hausa speaking extends up north to Libya and there are probably about over a million Hausa speaking people in Sudan. Saudi Arabia has a large Hausa population. Hausa people are adventurers and reach many parts of Africa for trading. They are found as far as Congo and Zaire.
I understand that Hausa is the first or second most widely spoken language in sub Saharan Africa .
I hope above piece throws more light on the extent Hausa is spoken in Africa and beyond.