These are written in the Fula language. Many others exist in Hausa, Wolof and other languages.
Here’s more pictures showing more modern uses of the Ajami script:
The social and commercial life of African Ajami | Africa at LSE
African Ajami is a centuries-old practice of writing different languages using modified Arabic script, deeply embedded in West African histories and culture.
blogs.lse.ac.uk
Aside from Ajami scripts, Arabic was a sort of literal lingua franca for many West African and Sahelian Muslim communities. Niger alone has a Musuem containing 4000 Arabic manuscripts.
