Learn Hardcore Hausa: Aisha tana nan?

Aisha = the person’s name
tana = a feminine singular subject marker used in this kind of present/ongoing-state sentence
nan = here, around, or present, depending on context

So the sentence is built as subject + subject marker + location/presence word.

Why is tana needed if Aisha is already the subject?

Because that is a normal Hausa sentence pattern. When you use a full noun like Aisha, Hausa still usually includes an agreeing subject marker after it.

So to an English speaker, it may feel a bit like Aisha she is here?, but in Hausa this is standard grammar, not unnecessary repetition.

Does tana simply mean is?

Not exactly. It is better to think of tana as a feminine singular subject marker for this kind of clause, rather than a direct one-word equivalent of English is.

In some sentences, English is will correspond to tana, but not always. Hausa handles to be differently depending on the type of sentence.

Why is it tana and not yana?

Because is feminine. Hausa marks gender in the third person singular.