docs: fix typos and grammer

[rasa]

No description provided.

[shirou]

Thank you so much!

However, according to this page, it seems "my native language" or "my mother tongue" is a commonly used. "my native tongue" is also commonly used? Sorry, I am just wondering.

[rasa]

However, according to this page, it seems "my native language" or "my mother tongue" is a commonly used. "my native tongue" is also commonly used? Sorry, I am just wondering.

I'm humbled that you caught that mistake, "native tongue" is definitely not correct. I've fixed it.

[shirou]

Great, thank you so much!

[rasa]

I'm glad we corrected it, but "native tongue" is used on occasion. See https://en.m.wikipedia.org/wiki/First_language .

[shirou]

I see. However, from English learner perspective, "tongue" is not a familiar word (rather than "language" at least), so "native language" is better for me.

Anyway, thank you for your kindly contribution!