I am not sure about audiogames that would teach such a young child who hasn't presently spoken English. www.7-128.com have some available I believe, however if you post a topic in general game discussion its likely people will have ideas, especially as we have several members who are from Thailand who speak both Thai and English thus might be in a good position to discuss the language issue.
@Dan welcome to the forum, glad you liked my list, Mrs. Dark is getting to be quite a fan of caves under thorn hill .
The list was more intended as a guideline since while it is eventually planned to add as many alexa aps to the audiogames.net database on this site as I there aren't that many of us who are working on it .
Discussion of what makes an audiogame engaging though is just the sort of thing we'd be up for here, so feel free to post a topic in general game discussion and you'll likely get some interesting opinions (I have some myself).