The thing is, I'm trying to limit the words to things that are already in his vocabulary so that he can more easily come to realize that these letters are a way of expressing concepts he already knows. And since the kid is a Taglish speaker (more heavily weighted towards Tagalog than English, I'd say), I've been using both Tagalog words and English words in these exercises. (His schoolbooks are in straight English.) His words so far are ate, apple, araw, bata, ball, blue, baboy, car, camera, cat.
I'm wondering what you all think of this strategy. Do you think it's an okay way to focus on getting him to associate sounds with letters/words? Or will it be detrimental in the long term to indiscriminately mix languages like this?