We aren’t doing ourselves any favours with this line of thinking.
So there’s agreed-on international English (your “formal” English) & there’s agreed-on regional variants, like US, UK, Australian and yes, Nigerian. Plus sub-variants of each of those.
Did someone say “correct” English?
This thinking, unspoken, is behind much of the pushback.
Nigerian English has “trafficate” & “rain is falling” & “pick bike.”
Nigerian English is a thing you guys. So’s Pidgin English. (Or did we actually need @PidginBBCNews to validate us first?)