Language and identity are two different entities. Speaking a language doesn’t automatically make you have the identity originally associated with that language. A lot of people speak English but do not identify as English/British. I suspect the same applies to African languages.

For example, if you asked a person who spoke Somali during the precolonial times who he identified as, he’d probably mention his clan. The clan preceded his ‘tribe’. The clans had different cultures initially but the common language made ideas and practices spread easily among them.

The primacy of the clan is made even more obvious by the proliferation of flags for the different Somali clans in recent times. Almost as if the clans are separate nations. So, the whole idea of there being an overarching ‘Somali’ identity is probably a modern development.

There is a high chance that a good number of people who currently speak the Somali language did not originally identify as ‘Somali’ and probably had their own languages. They just used it as a lingua franca and their original languages were lost to history.