Maybe I just quibble about the detail, but in my opinion the process of learning my own native language is still considered to be "language learning", hence it's sufficient to asking here. I think changing the site name to "Foreign language learning" will avoid this.
What's your thought?
Yes, they are on-topic
The description might be a bit misleading, especially at second-language acquisition. But, the title speaks for itself.
Asking questions which deal with learning of any language is(should be) perfectly on-topic, even if it's learning or getting better at a native language.
I wouldn't be too happy with a question on this site that was "only" about the English language (my native language), because there are English Language and English Language Learners sites on Stack Exchange.
But I feel that a question about an English word or construction as it is derived from, or otherwise relates to a second (non-English) language, would be on topic.
learning when to use who and whom would be off-topic if you posted, but on-topic if I posted it? Just because I am not a native English speaker? That doesn't seem logical.